Two different step drivers?

I have a 3 axis xylotex that has been working great with linuxcnc, but now I want to add a fourth axis using the tb6560 driver I purchased off ebay. Stepconf only asks what kind of driver board you have, not separate settings for each axis. Can I keep the quick pulses on my three axes and add the cumbersome, slow steps that this new board requires? Surely this can be done by editing the ini and hal files, but why not in stepconf wizard?

yes this can be done by hand editing the hal and ini files , although I have never try'd it

stepconf is only an aid in preparing a first configuration , to the point of having the major parts working , and then it is up to hand editing to further tune the configuration further .