Oh, tell me about it...!
As I have two extending ladders now (had to buy the second because the original wasn't long enough fro a long-term project I was working on) I've ended up storing one of the ladders with the roof kit permanently fixed.
My other difficulty is that living in what I've recently discovered is an "arts and crafts"-style property, the roof is very long and steep, which means that the distance between ridge to eaves is longer than the length of any single ladder - therefore I have to use an extension ladder as the roof ladder. That's problematical as it means that as you climb it, the lugs on the upper section which normally hook over and lock the rungs of the lower section are being loaded in the wrong direction (IYSWIM). Furthermore, being two sections, the lower face of the ladder in contact with the tiles is staggered (IYSWIM), so to present a flush face (and therefore even loading) to the roof, I need to attach lengths of timber to each rail of the lower section. Sounds a bit Heath Robinson but all that's achieved with very firm strapping etc, and is as safe as a single-section ladder would be. But takes an age to set up (which is why we had no channel 5 on the TV for most of the winter!)
David