Create a Thread in Rotor's code

Hi everyone,

I am modifying the source code of fjit.cpp to create a thread that it
executes native code (generated by FJIT).  Thread jumps correctly to
this code, but when it tries to execute the code corresponding to helper
gives an error of memory access violation.  Concretely one is the call to
the GetThread() function.  The following scheme sample that is what attempt
to do:

-----------------------------
void *myThread(...){
   while (true){
      while(not_active);
      jumps_to_users_code;
   }
}
-----------------------------
users_code:
   .
   .
   call  JIT_PoolGC()
   .
   .
-----------------------------
void JIT_PoolGC(){
   Thread *thread = GetThread(); <- ERROR !!!
   .
   .
}
-----------------------------

Thread I create throught the call CreateThread(...) but I must to use the
structures that sscli for the management of threads provides (structure
THREAD), since the error appears when it consults this structure.  How can
I do this?  Where can I find information specifies?

Thank you and excuse my english...

Hamnet