Tips for Building LOB Apps for the Windows Store

Been playing around with the new Live Tile support.
Not having much luck getting it to work. Go to Pin the site to Start, most of the time I don't get the option to use the 'large' tile, although once out of about 10 attempts it did work.
Not having much luck getting any Live Tile updates at all, URLs all check out, can access the XML just fine from the server myself.
Tried both having the stuff embedded in the head of the file and using browserconfig.xml Doing my testing on a Hyper-V box running 32-bit version.
Can anyone else report any success?
OK, seems to be sorted, bar the large tile size not always being available when pinning - and when it does the image doesn't always seem to load.
FTP client was adding some null bytes to the .xml (facepalm), that was upsetting it + feed had invalid language specified, someone used en-UK rather than en-GB!
But yeah great stuff, and ta muchly for providing the backend service for it! Save me faffing about for a few hours jiggling up some skins on my blog to handle it.