Win2k printer Driver

I am developing a Rendering Plug in for Univeral Printer Driver for Win2k.I am
trying to get the Data from the DrvTextOut function which i have hooked
as i want to do some pre processing on it before it goes to the spooler.

I am getting the StrObj structure from the DrvTextout function ,but if i
try to Enumerate the Glyphs using
STROBJ_vEnumStart(pstro)& STROBJ_bEnum functions the driver does not
work at all.
Is teher some other way by which i can get the Data which is sent by the
GDI for rendering.