Once again, yes, it is supported.
Since you did get the prompt and you did install the enhancements on the target machine, it should be available.
I will note that there are times when things are funky and a PC will show unavailable for unknown reasons, though it is indeed available. If you have access to the remote machine, try rebooting it and signing into Live Mesh again.
If it still doesn't show as available, go ahead and submit a bug report with logs from that machine.
How to Submit Bugs and Live Mesh Logs
Note that you may not receive a response to the bug report, though. It will be transferred to the internal system to be assigned to the appropriate development group.
-steve
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