We had an issue with Running Central Administration over SSL as already posted by Spencer.
Good News! There is a fix in work and is in planning for the October CU! (KB 2394320)
What is the issue?:
When you have changed your Central Administration (CA) to listen on Port 443 / SSL and you have User profile synchronization service configured, we had the problem that the MIIS Manager tool (FIM Agent) was not aware of the HTTPS (SSL) port and URL.
When you start the MISSClient.exe tool (located here: c:\Program Files\Microsoft Office Servers\14.0\Synchronization Service\UIShell\miisclient.exe), you can click on the tab "management agents".
There you'll find some entries like "ILMMA" and also "MOSS-<GUID>". On right-click on the "MOSS-<GUID>", going to properties and then selecting "Configure Connections" you may see the default setting as shown here:
The "hack" would be now to change the "Connect to:" field and replacing the "direct://…" part with "https://…"
Although this "trick" works, any manual changes to the FIM agent tool is still not supported and we also do not recommend this at all!
there is a fix in work that will address this problem and is planned to be released with the October CU 2010!
When switching the central admin from SSL to standard or otherwise, it might be best to reboot the server (recall, User profile services etc. has to run in a special relationship and order and manual doing things are mostly will fail!). If not, the management agent will not find the UPA and sync will fail!