I tried it once about two years ago, just for fun. I did it with ActivePerl's PerlCtl. From what I remember it didn't work that well. I had a hard time getting it working and getting SilkTest to understand it. Maybe both ActivePerl and SilkTest are better now. Haven't tried since. Let us know if you get it working.
What were you hoping to do with Perl inside the tool?
I haven't tried anything like that, but I do use Perl extensively to build scipt files to run. I use SilkPerformer, so starting with a known base of tests, I can create a new bdf, wdf with minimal work.