Let me answer your question a little further on the third paragraph.
Yes i have done a conversion from vmware to hyper-v. It works very smoothly and you should not have any problems. It is best to do the conversion while the source is offline.
what you will need to do is setup a server (probably the one you have VMM server on) as a hyper-v server.
You will convert on your servers to hyper-v to this box using vmm 2008. Once completed and you have tested the vms to make sure they work correctly. Create a backup of your vmware images and hyper-v servers. Format the vmware server and install hyper-v. I would highly recommend server core edition. the use VMM 2008 to migrate the VMMS to the new hyper-v server. the entire process should take about 10-14 hours of your time. assuming you have a build a vmm2008 server