I do the same thing with my Arcam A32. In fact, it is one of the options described on the manual.
Bi-wiring using both speaker 1 and 2 outputs
I have a McIntosh MA6450 integrated amp. The amp supports two pairs of speakers and allows both pairs to be on at the same time. Currently, I am using this feature for bi-wiring purpose. That is, I connect one pair of cables from "speaker 1" to the low-frequency posts and another pair of cables from "speaker 2" to the hi-frequency posts. It works fine. Are there any protential problems with this kind of wiring?