diff --git a/Nuclex.Support (net-2.0).csproj b/Nuclex.Support (net-2.0).csproj
index fca6981..9ec054e 100644
--- a/Nuclex.Support (net-2.0).csproj	
+++ b/Nuclex.Support (net-2.0).csproj	
@@ -18,7 +18,7 @@
     <DebugType>full</DebugType>
     <Optimize>false</Optimize>
     <OutputPath>bin\net-2.0\Debug\</OutputPath>
-    <DefineConstants>TRACE;DEBUG;UNITTEST;USE_XMLDOCUMENT</DefineConstants>
+    <DefineConstants>TRACE;DEBUG;UNITTEST;USE_XMLDOCUMENT;NO_EXTENSION_METHODS</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <DocumentationFile>bin\net-2.0\Debug\Nuclex.Support.xml</DocumentationFile>
@@ -27,7 +27,7 @@
     <DebugType>pdbonly</DebugType>
     <Optimize>true</Optimize>
     <OutputPath>bin\net-2.0\Release\</OutputPath>
-    <DefineConstants>TRACE;UNITTEST;USE_XMLDOCUMENT</DefineConstants>
+    <DefineConstants>TRACE;UNITTEST;USE_XMLDOCUMENT;NO_EXTENSION_METHODS</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <DocumentationFile>bin\net-2.0\Release\Nuclex.Support.xml</DocumentationFile>
diff --git a/Nuclex.Support (xna-3.1-xbox360).csproj b/Nuclex.Support (xna-3.1-xbox360).csproj
index a6394af..df6fd49 100644
--- a/Nuclex.Support (xna-3.1-xbox360).csproj	
+++ b/Nuclex.Support (xna-3.1-xbox360).csproj	
@@ -18,7 +18,7 @@
     <DebugType>full</DebugType>
     <Optimize>false</Optimize>
     <OutputPath>bin\xna-3.1-xbox360\Debug\</OutputPath>
-    <DefineConstants>TRACE;DEBUG;XBOX;XBOX360;USE_XMLDOCUMENT;NO_SERIALIZATION;NO_SYSTEMEVENTS;XNA_3</DefineConstants>
+    <DefineConstants>TRACE;DEBUG;XBOX;XBOX360;USE_XMLDOCUMENT;NO_SERIALIZATION;NO_SYSTEMEVENTS;XNA_3;NO_EXTENSION_METHODS</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <NoStdLib>true</NoStdLib>
@@ -30,7 +30,7 @@
     <DebugType>pdbonly</DebugType>
     <Optimize>true</Optimize>
     <OutputPath>bin\xna-3.1-xbox360\Release\</OutputPath>
-    <DefineConstants>TRACE;XBOX;XBOX360;USE_XMLDOCUMENT;NO_SERIALIZATION;NO_SYSTEMEVENTS;XNA_3</DefineConstants>
+    <DefineConstants>TRACE;XBOX;XBOX360;USE_XMLDOCUMENT;NO_SERIALIZATION;NO_SYSTEMEVENTS;XNA_3;NO_EXTENSION_METHODS</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <NoStdLib>true</NoStdLib>
diff --git a/Source/StringHelper.cs b/Source/StringHelper.cs
index ac91870..596c6e3 100644
--- a/Source/StringHelper.cs
+++ b/Source/StringHelper.cs
@@ -37,7 +37,11 @@ namespace Nuclex.Support {
     ///   <paramref name="anyNotOf" /> array or -1 if all characters in the string were
     ///   present in the <paramref name="anyNotOf" /> array.
     /// </returns>
+#if NO_EXTENSION_METHODS
     public static int IndexNotOfAny(string haystack, char[] anyNotOf) {
+#else
+    public static int IndexNotOfAny(this string haystack, char[] anyNotOf) {
+#endif
       return IndexNotOfAny(haystack, anyNotOf, 0, haystack.Length);
     }
 
@@ -55,7 +59,11 @@ namespace Nuclex.Support {
     ///   <paramref name="anyNotOf" /> array or -1 if all characters in the string were
     ///   present in the <paramref name="anyNotOf" /> array.
     /// </returns>
+#if NO_EXTENSION_METHODS
     public static int IndexNotOfAny(string haystack, char[] anyNotOf, int startIndex) {
+#else
+    public static int IndexNotOfAny(this string haystack, char[] anyNotOf, int startIndex) {
+#endif
       return IndexNotOfAny(haystack, anyNotOf, startIndex, haystack.Length - startIndex);
     }
 
@@ -75,7 +83,11 @@ namespace Nuclex.Support {
     ///   present in the <paramref name="anyNotOf" /> array.
     /// </returns>
     public static int IndexNotOfAny(
+#if NO_EXTENSION_METHODS
       string haystack, char[] anyNotOf, int startIndex, int count
+#else
+      this string haystack, char[] anyNotOf, int startIndex, int count
+#endif
     ) {
       int anyLength = anyNotOf.Length;
 
@@ -105,7 +117,11 @@ namespace Nuclex.Support {
     ///   <paramref name="anyNotOf" /> array or -1 if all characters in the string were
     ///   present in the <paramref name="anyNotOf" /> array.
     /// </returns>
+#if NO_EXTENSION_METHODS
     public static int LastIndexNotOfAny(string haystack, char[] anyNotOf) {
+#else
+    public static int LastIndexNotOfAny(this string haystack, char[] anyNotOf) {
+#endif
       return LastIndexNotOfAny(haystack, anyNotOf, haystack.Length - 1, haystack.Length);
     }
 
@@ -123,7 +139,11 @@ namespace Nuclex.Support {
     ///   <paramref name="anyNotOf" /> array or -1 if all characters in the string were
     ///   present in the <paramref name="anyNotOf" /> array.
     /// </returns>
+#if NO_EXTENSION_METHODS
     public static int LastIndexNotOfAny(string haystack, char[] anyNotOf, int startIndex) {
+#else
+    public static int LastIndexNotOfAny(this string haystack, char[] anyNotOf, int startIndex) {
+#endif
       return LastIndexNotOfAny(haystack, anyNotOf, startIndex, startIndex + 1);
     }
 
@@ -143,7 +163,11 @@ namespace Nuclex.Support {
     ///   present in the <paramref name="anyNotOf" /> array.
     /// </returns>
     public static int LastIndexNotOfAny(
+#if NO_EXTENSION_METHODS
       string haystack, char[] anyNotOf, int startIndex, int count
+#else
+      this string haystack, char[] anyNotOf, int startIndex, int count
+#endif
     ) {
       int anyLength = anyNotOf.Length;