Hi Peter,
The quick answer is that OCUM 5.1 will work with WFA 1.1. I've done it where OCUM 5.1 is on Linux.... You'll need to do the 'regular' oc5setup process as identified in the Installation and Setup document, but it does work.
However, you won't automatically get anything new from OCUM 5.1. The cm_storage schema in WFA is still aligned with what is available in OCUM 5.0. If you are going to ask when will the new OCUM 5.1 tables be available in the certified WFA cm_storage schema? Officially right now that is slated for WFA 2.0 (Q4CY2012), but we're hoping it can be available before then.
Since OCUM 5.1 is c-mode only, even though both the cm_storage and storage schemas in WFA will "work", only the cm_storage schema will be populated with data since there will be no 7-mode data available in OCUM 5.1 for the storage schema
Hope this helps,
Kevin