Hi there,

I realise this is a bit of a complicated overview, but I'm writing this with not little time - there may be a simpler way (Nokia Qt SDK) but I don't have time to check it works - I need to get up at 6am to travel to Oslo tomorrow.

First things first, make sure you've got scratchbox configured to use ARMEL (the architecture of the n900):
sb-conf se FREMANTLE_ARMEL

Next step: you need to install git inside scratchbox (via apt-get). Should be something like:
fakeroot apt-get install git-core
(may be git, I can't remember the package name offhand)

After that, you'll need to 'fork' rotatedaemon's source (so you can do what you want to it.
Go to http://github.com, sign up, then go to http://github.com/rburchell/rotatedaemon once you're logged in and click the 'fork' button on the top right.

It should give you some pointers how to download the code, and you should be able to start digging around.

Familiarise yourself with what is there a bit, start experimenting a little if you want (and if you have the ability to) - feel free to mail me questions directly if you get lost on *anything*, I'm always happy to help:
viroteck@viroteck.net

Note: I'm going to be in Oslo for the next two days, quite busy. So my responses will be slow (if at all) until I get back on Wednesday.

[edit]:
sorry for the really crap instructions, but I really need to get to bed, so no time to write up proper ones or proof-read this. hopefully it gives you some pointers in the right direction.