Even though I've got a number of servers with space to spare for my Mac backups I keep them separate as its less hassle.
I bought a 3rd gen Time Capsule from the Bay and then picked up a cheap 3TB WD Green from OCUK's Clearance Lines section to upgrade it. That was my Mac backup sorted for not much £'s and it 'just works'.
You can apparently use the OSX Disk Utility to create a sparse bundle, copy it to your Microserver share and then use the tmutil terminal command to associate the bundle with Time Machine. Sounds like hassle though whereas a TIme Machine can just be set and forgot (and works as a great extra wireless access point too!).
ive actually never used time machine which i think is a good thing. after doing some more reading i dont think id have much trouble whichever os i used.
i use carbon copy cloner to clone my mac hdd currently. every other day overnight it clones it.
it doesnt touch files which are present on the destination but not on the hdd and files which have been changed gets moved to a temp folder and the new file in its place (versioning)
i can still use this and just set a folder on the server as my location. if i use WHS then i can get Crashplan running easily so that will then make a cloud (offsite) backup of the folder i specified in CCC as my destination.
pretty sure im going to go this route now so better get on and order it.