OK... let me clearify...
The year-old power bar was in the stoker's handlebar bag....
which is this Jandd bag
http://www.jandd.com/detail.asp?PRODUCT_ID=FBB
only in black which can be found here if you look:
http://www.precisiontandems.com/catframeaccess.htm
Stoker had knee-interference issue also untill I zip-tied the bag to the stoker's stem in a forward position.