Why rewrite your Perl code in C?? Just because you have some XS code doesn't mean you have to do every single thing for that module in XS code!
Do in C, only the stuff that is easy in C. Use a wrapper subroutine written in Perl to do stuff like what you are trying above. The code you have above is the kind of code that breaks when a new version of Perl comes out (or doesn't work when someone tries to use it on an older version of Perl than the one you developed it on).
I've done this quite a bit and have been extremely happy with the results. I find I can make modules with much nicer, Perlish interfaces than I see in other XS modules. Plus the code ends up being much easier to understand, maintain, enhance, and debug.
(but my friends call me "Tye")