Call to build-in operator from new operator

Greetings,

I don't really know if this is the correct place to ask this question, if not please
direct me to the correct mailing list.

I'm trying to develop a new operator for PostGreSQL (actually for TelegraphCQ, which
is an extension of PSQL). Part of the operator's procedure is the @-operator. So now
my question is: How do I call the on_pb function from inside my own function?.
The on_pb of course takes the argument 'PG_FUNCTION_ARGS' which is defined in fmgr.h
as 'FunctionCallInfo fcinfo' which is defined as pointer to 'struct
FunctionCallInfoData', so my question boils down to:

What do I put into this struct to call 'on_pb' with two arguments from the call to
my function?

Further, is there a way to access data in tables in the database other than those
given as arguments to the function? And how?

Sincerely
Kim Bille
Department of Computer Science
Aalborg University
Denmark

--
"Mind are like parachutes --- they only work when open"