A solution
Thinking out of the box on this one; I just had an idea and it works!
Add the XP Virtual machine inside parallels as one of your Logmein computers (I did it with Pro, but I'm sure it will work with Free as well):
From within XP in Parallels, use your browser and log into your Logmein acct (while you're sitting at the Mac, so you can type the @ sign in your email address). Hit add computer and install the client. Now whenever parallels is running, you'll see the XP virtual machine in your list of computers in your Logmein acct. You can now bypass the iMac and remotely log directly into the Parallels virtual XP machine.
Works like a charm. All keyboard functionality is there. Just like you connected directly to a Windows machine.
If you're away and your iMac is up but parallels is not running, connect to the iMac first, start Paralllels, disconnect and then connect to the XP "machine".
Good Luck,
~ truegravity