I bought one a few month ago. Now I believe the battery's dead already
. So I tried to change it (basically sending it back for replacement would nearly cost its price, so I thought it'd be better to do it myself).
Unfortunately it's all glued and welded together. Once you remove the 4 screws on the back, you have to pull hard to unglue the circuits from the top plastic part (where the buttons are). Then you have to unscrew two more very little tiny screws to remove the the circuit board from the bottom. There is the battery, on the board... but the contacts are welded (2-points)! Cheap electronics! They basically won't go!
Now my remote is definitely dead I think.
So to answer i_trax' question: no, you can't change the battery (it's a CR2025 by the way). But not because it's weather sealed (you could replace the seal pretty easily I think), but because it's cheap electronics.