I have got a problem with upload to extras devel. I want to upload an application for watching internet TV's. It is basically a complex bash script (placed in /usr/bin), so it does not require compiling and it runs on all architectures.
I have managed to create proper .deb package which installs and runs perfectly on my N900 (deps are just mplayer, bash, sed, wget, grep).
The problem is - when I try to upload it to extras-devel, I need a .changes file, .dsc file and source file. How do I make these?

I tried to make my own .changes file in a text editor and I managed to upload it, but when I upload .dsc and tar.gz ("source" I made by simply packaging the script), it says the MD5 sum doesn't match (although I did md5sum's correctly). I think this is not the proper way to do it anyways, so what is?

Thanks for your answers, in advance.
PS: Is there any way to do that on N900 itself? dpkg should be enough for packaging, but it'd be nice to have something more 'user friendly'...