Hi uidzer0,
A couple of things to look at:
1) What version of VMAN do you have installed? I highly recommend you install at least version 6.0.1 of VMAN as we included some critical fixes for Hyper-V cluster association in that Service Release.
2) Are all of your Hyper-V clusters appearing in the VMAN interface correctly?
3) Make sure that all the Hyper-V hosts in a cluster are added as a single datasource for VMAN Collection.