[Users] textops from other module

Hi, I want to perform a textops function, namely subst, over a SIP message. But I want to do this not from the openser script but from a module I'm about to implement. Unfortunately, the textops module did not provide an API to other modules. But I'm wondering whether it is more than simply removing the 'static' from the function declaration of the subst_f function in textops.c to make this function accessible for other modules. Or do I have a chance to set a pseudo-variable or AVP with the complete regex in one of my own modules functions and perform the subst using that pseudo-variable or AVP in the openser script directly after the call to my own function? Or is the only way to re-implement the subst_f functionality in my own module to use it from there? Thank you very much, Wolfgang