Maybe you can show us some short testbed code where you try your regular expressions against some C# example code?

Please also show us the .net regular expressions, and your effort to translate those to Perl. Most likely, .net regular expressions are basically the same as Perl regular expressions, except that .net likely uses strings where Perl has a special syntax for regular expressions. If that is the case, you can likely get away by simply replacing all double backslashes (\\) in the .net regular expression by a single backlash (\) for Perl.