Dude, I just glanced at the on-line manuals for those amps and whatever you do, DON'T connect the Extension Speaker Cabinet output from the Traynor to the "Amp In" of the Behringer! As I read the Behringer manual, that's actually a PRE-AMP in, and running expansion cabinet signal through it could very possibly do immediate and permanent damage. It LOOKS like you should, however, be able to patch the FX Out of the Traynor to that Amp In, and have the bi-amping configuration I was talking about.
'berger XL-2 => EBS HD350 => EBS Neo212
Steinberger Club #0013, Pedulla Club #147, Pre-EB MM Club #44 , Epiphone #90, EBS #34