APEX

I have an AJAX process which adds a number of additional arguments that get passed through the URL, i.e. "&argname=" that are not supported via htmldb_Get or the "f" procedure. As a work around I have created my own PLSQL wrapper around the function which has these additional arguments which works fine, and I simply alter the URL string i.e. "p" before calling the "f" procedure in this PLSQL wrapper.

However this will not work when session state protection is enabled as when I call "prepare_url" to generate a checksum on my newly altered URL it returns null as expected because I'm outside of the APEX engine. So the question is is there any way I can generate a checksum in this wrapper procedure. I have a valid APEX session and cookie can pass though all the needed details.... I have had a good look through the APEX API's but can't find anything. Can anyone help?