2001 E430 Remote Trunk Opening

[waybomb]

Hello
Having a problem with my 2001 E430 Sport trunk lock. The trunk unlocks with either key. However, it does not pop open.

It will pop open with the switch in the console. So the electric unlock works, or is it vacuum? In any event, it works.

I can not get the metal key to turn either way in the trunk lock. The metal key works on the glovebox. I'd like to get the metal key to work - how is the trunk loock removed so I can lube it and free it up?

If I understand the thing correctly, if the trunk is locked manually with the key, the trunk can not be unlocked with the fob. But I can unlock it with either remote key.

So, any ideas on where to start looking for the source of my problem?