What remote fob do you have? The best fob is the Webasto T91, that's the one I've got, cos it's smaller than the standard T89/T90 fob and is easier to program. You can also download the handbook from the Webasto website.
The best way to program the fob is as follows.
1. Remove the battery from the fob. CHECK the battery is OKAY, it won't synch if the battery is old or low on charge.
2. Locate the Webasto FBH receiver behind the fuse panel in the rear RH section of the boot.
3. If you can reach the power lead without unscrewing the fuse panel to gain access, then you just need to (gently) pull out the power lead connector (that's the lead on the RHS of the receiver, it can be fiddly to remove the connector so be careful).
4. Wait for at least 30 seconds, then put the fob battery back in.
5. Reconnect the power lead to the FBH Receiver and simultaneously press and hold the OFF Button until the light flashes on the fob (at least 10 seconds).
This should synch the fob to the receiver, but sometimes you have to do it a couple of times to get it sorted. As I said previously, it will either work first time or be a right fiddle.
Good luck.