How are you bringing the HDV material into your system?
What are you editing this material as (uncompressed HD or SD or...?)
I have been able to "hotwire" the Xena to run when I'm in the Adobe SD SDI preset (I assume it would work similarly in the Adobe HD-SDI preset) where I launch Machina in the background and set it for the primary output I need (SD analog out or HD SDI out...framesize, etc.) and tell Premiere Pro to output to the external device.
Whether or not it would solve the multicam issue or not is another question...I'm afraid I don't typically work with multicam in my work, so I'm not as aware on all the idiosyncracies that may be present in that feature...
TimK,
Director,
Kolb Productions,
Creative Cow Host,
Author/Trainer
http://www.focalpress.com
http://www.classondemand.net 
