You add it to the SqlFunctionAttribute in the C# code:

public partial class CTSStoredProcs

{

[Microsoft.SqlServer.Server.SqlFunction(IsDeterministic=true, IsPrecise=true)]

public static SqlBoolean RegExValidate(

SqlString expressionToValidate, SqlString regularExpression)

{

Regex regex = new Regex(regularExpression.Value);

return regex.IsMatch(expressionToValidate.Value);

}

}

... nothing different on the T-SQL side.