I'm not familiar with the IA product -- but the DR550 is simply TSM on specialized hardware. You should be able to use 'Export Node' to copy node data over to a new TSM server. The snag here is that I think the DR550 runs TSM 5.5.x -- and I'm not sure about the compatibility of data exported from 5.5.x into the newer versions of TSM, like 6.3, which have an entirely different database structure.
Alternately, you could just pick-and-place the data from the DR550 to all new hardware rather than going through the export/import cycle.
It's going to be interesting, that's for sure...
-JD.