How do you re-insert those door sensor cover things?

[Reducto]

I just finished painting my van (pictures coming soon) and have not been able to get those rubber things back on! They're the ones that cover the door open sensors on the front doors and each has two little bulbs that fit into holes in the body. They came out easy enough but won't go back in - the rubber just compresses. Any tips?

[Burntboot]

Usually a tiny flat blade screwdriver can be used to assist those things, just make sure it doesn't have any sharp edges or you'll be buying new rubbers.