By default, the FileVault 2 Login Screen comes up before the OS boots, preventing you from accessing it remotely via SSL or Screen Sharing.
Apple provides a utility that, when executed, will save your username and password in the system memory and use it one time (then clear it) to proceed past the FileVault 2 Login Screen.
Open Terminal and execute the following command. Be careful though, as it will cause an immediate reboot of the system (as though you used the shutdown command):
sudo fdesetup authrestart
After the reboot, your hard drive will be unlocked and you will be presented with the standard MacOS Login Screen (as though you do not have FileVault 2 enabled).
Not every Mac supports this command though. To find out if yours does, you can execute this command:
fdesetup supportsauthrestart
If the response is "true", then you're ready to reboot.