You can add your custom entries in /ubcd/custom/custom.cfg (or in the UBCD config files /ubcd/menus/syslinux/)
For Windows 7/Vista, you need this:
MENU LABEL Boot Windows Vista/2008/7 (bootmgr)
You can't add Ubuntu live in its original form (with the nice boot menu), but if you know which options you select to boot it, I can try to give you the right command line.
Which version of Ubuntu?
You can read how the boot entries work, by donwloading the Syslinux package and by reading the documents in /doc.
Download Ultimate Boot CD v5.0
Use Parted Magic
for handling all partitioning task: http://partedmagic.com/