I have not tried the theory that I proposed with the DPA box / Senn mics..
Both the Senn and DPA mics operate from a two wire 9v design; same voltage, same supply feed. I'm entirely confident that it would work - but I have not actually tried it.
It was this box that I modified:
http://www.dpamicrophones.com/en/products.aspx?c=Item&category=139&item=24262The box is for DPA 406x miniature omnis. The 406x series has what are called microdot connectors; essentially a proprietary miniature screw-in coaxial jack. I wanted the microdots for making a longer cable set for the mics, one that could be plugged into a single stereo jack for powering.
So, there were two microdot inputs in the batt pack, and I picked them out.
They were replaced with a redundant pair of stereo inputs; redundant, such that, if one stereo jack crapped out, the other was there for backup. The stereo jacks were bolted into the place of the microdots. This mod allows powering of other 9v two wire mic designs from other companies, by removing the proprietary connectors
The mod was easy, and anyone half qualified with a soldering iron could do it.
It could probably be done in such a way as to allow you to choose between your Senn batt pack, or, the DPA batt pack, with an inline cable-to-cable mini-xlr_type connector, or something like that, for a lockable connector.
I'd take a pic for you, but my house is torn up for ceiling texturing and painting right now.
DPA will sell direct, at full retail. You'd be better searching for a competitive retailer.