The possibility to integrate UBCD and Ubuntu into 1 UFD (USB Flash Disk) depends on the way you prepare the UFD (filesystem, bootloader, BIOS settings, specific bootable UFD...), more than it depends on UBCD or Ubuntu.
Personally, I don't see the point in using the same UFD for a "regular" OS and for a "maintain/repair/administration" tool, and maybe there is no much actual experience in making such an UFD in this forum. Maybe that's why you didn't receive suggestions here?
I can think about several possibilities, according to your goal.
You could search
for more general solutions, like installing "Linux and UBCD" (PartedMagic is included already, and there are other tutorials and similar troubleshooting questions at this UBCD forum and at the UBCD Wiki http://wiki.ultimatebootcd.com
for other distros) instead of "Ubuntu and UBCD", and from that start point, try to reproduce the general method with a specific Linux distro.
In any case, you should try to use the latest available versions of the tools, not just the versions mentioned in a specific tutorial, except for cases where you find specific suggestions / recommendations for specific "previous" versions.
If you want to try RMPrepUSB as suggested in the tutorial at the UBCD Wiki http://wiki.ultimatebootcd.com
, you should search
for the specific RMPrepUSB forum at boot-land.net. There might be useful tips also at the RMPrepUSB website.
Using RMPrepUSB or any other similar tool, besides the methods you may find at their forums, you could try the complete "ISO" method, which includes several complete ISO images in 1 UFD, and the boot process expands the ISO image each time you boot. There are pros and cons for this method.
Another possibility is to use a "maintain/repair/administration" tool that is based on Ubuntu, as for example Ubuntu Rescue Remix, if this is more close to your actual goal.