Sorry but I been very busy lately.

Most lua functions are just wrappers for functions of wireshark's
"API". Don't use the Lua wrappers, use the very same C functions they
use instead, you can use the code in them instead!

you can take the code in wslua_retap_packets() and
wslua_register_menu() and instead of fetching the parameters from the
lua_State you should get them yourself.

BTW
I do not see any good use in a dissector for retap_packets(), which
kind of plugin are you working on?

Luis