Key fob replacement W124 (95)

[tim124]

The single push-button for remote door-locking/unlocking on my W124 key fob is working only intermittently; so I have purchased a non-OEM key fob in the expectation of either being able to install the existing circuit board and battery holder into the new casing, or just using the new switch in the old fob. However, whilst the replacement fob can be readily opened, I can't find a way of doing the same on the old one, so I assume it is glued (?): is that the case? - and is there a special technique for opening it up without causing irreparable damage? (The vacuum locking mechanism itself is working OK - I checked using the key on the passenger side lock.) Thanks for any advice.