This is a rather late answer, but it sounds like you're confusing the MTConnect agent with an MTConnect adapter. Your software probably expects to connect to an MTConnect agent, which does serve XML data in both v1.1 and v1.2.
An adapter is a component that sits between the device and the agent. Most end-user software wouldn't talk to an adapter: it serves data to the agent in a pipe-delimited format that looks something like:
2010-09-29T23:59:33.460470Z|Xact|1.4198908806|Yact|-0.7842678428There's an MMS Online article here that explains the difference.
If this is the problem, then you can download the stock MTConnect agent, and set it up to communicate with your customer's DMG/Mori Seiki adapter. You can find information on doing so here on the MTCUP wiki.