Using Jolida SJ-202a to biamp w/ CODA Unison 3.1?

HI. I just purchased a Jolida SJ-202a used on A'gon for a second system. I am currently running a CODA Continuum Unison 3.1 integrated amp to Soliloquy 6.3's. I figured, while I was waiting on other parts for the second system, I would try to hook up the Jolida and biamp the upper frequencies on the Soliloquys.

How would I use a second integrated to biamp the speakers? Is there a way to bypass the gain on the Jolida, allowing me to use the amp section only? Or, do I have to adjust the volume of both the CODA and Jolida every time I want to adjust the volume?

One other question-would using a digital amp for low frequencies and tubes for the highs sound weird? Or, should it be an interesting combo?
I have done a fair amount of bi-amping, although never with Soliloquays. I have a Technics horn system which I run with a Sophia tube amp for the mid range and tweeters, and the factory solid state amp for the horn subwoofer, and find the effect pleasing. Most consultants would direct you away from this activity, simply because of the different tonal signature of the different kind of amps. Also, the power requirements of the speakers may be troublesome with the relatively low output of the Jolida. In any case, what do you have to lose by experimenting? Avante Gard has a nice discussion in their literature concerning this issue, although perhaps more appropo for horns.This kind of stuff is always fun to do. The Jolida can be rewired to bypass the controls, or you can simply turn the gain up full and use your preamp to control the output, saving the amp for other uses. I also run a pair of Klipsch LaScalas with the same Jolida in a large room to good effect.