I've had the same problem with the EC5s. If there is not too much solder spilled down the side you can get them into the housing with a bit or force when they are still hot from soldering. The heat makes the plastic just pliable enough for them to go in. Careful not to burn your fingers and good luck if you ever want to get them back out.

Failing that, as Jamie says, a quick file to remove the excess will usually get them in.