You need to build a romfs to add software.
genromfs will build a romfs from a folder.
You can copy the binaries to that folder on your computer and build the romfs.
Suggest also flthdr -z <BINARYNAME> to compress your binary, as space is an issue.
You can either download existing romfs's, mount then copy to elsewhere to build folder structure, or you'll need to create the default folder structures. I think I have a script in this forums which does it for you if you look for it
(found it - http://www.openipcam.com/forum/index.php/topic,115.0.html
(only for /dev though) )
If you do the download existing route, then
mount -o loop -t romfs ROMFSFILENAME /mnt/myromfs
and copy to elsewhere.
Then add in your binaries.
Genromfs point to new location, and you have a new romfs to use.