This advice won't necessarily be specific to you because I use 1.5.2 and when (as with now) I was using 1.4.7 I wasn't actually using any FTB packs, just something I put together myself that is similar.
It is also difficult to know what you have already tried. If I give you any knowledge you already have its because I don't know if you have tried it yet so consider putting that info down. EDIT: Just noticed you put up your crashlog after writing this post. Thanks.
There is a way of using the FTB launcher to manually add mods to FTB packs. I don't use the FTB launcher but there should be some documentation around here somewhere - try checking the wiki.
If you have managed to get that far already and you are crashing, know that the most common causes of crashes are id conflicts. Before adding any mods to a pack, you must get comfortable with the minecraft folder. By default, (at least on windows) the minecraft launcher puts it in the roaming file. To access this type into the search bar in the start menu %appdata% and you should find the roaming folder. Open it and look for the minecraft folder. I think its actually called .minecraft. FTB might install it in a different location (I couldn't say where so you will need to find that out yourself or from someone else) or you may already have moved the minecraft folder. Either way, find that folder and open it.
The next thing to do before adding any new mods is boot up minecraft from your FTB launcher with ultimate installed. When you have loaded a world open the NEI menu. I can't remember exactly what buttons to press but eventually you will get through one of those buttons to a submenu that allows you to make an ID dump. Make sure that nothing is hidden (IE block ids shown, item ids shown), and it might be helpful to you to have unused item/block ids shown too. Generate an ID dump. The file will show up in your minecraft folder. This will give you a list of all used and unused item and block ids in your instance. You can open it in notepad.
When you install a new mod, as I said before, crashes will likely be due to id conflicts. If you read the crashlog it might tell you which ids are conflicting. If not, the id dump will come in useful.
There is another folder in the minecraft folder that you need to go into. The config folder. It contains all of the config folders/files that allow you to tweak certain features of the game or change item ids.
So now, you should install one new mod from the UE suite. The game might load successfully, but if it crashes don't worry. It should have generated a config file. Find it and open it. Look for the section that contains the ids. Read the crashlog to find out which ids conflict. Change them by looking for for vacant ids* in the NEI dump and rewriting the number in the config to a vacant id.
Restart minecraft and check that it works. Hopefully it does. Rinse and repeat for any other mod that you add. Good luck.
* Remember block ids (things placable in the world) must be below 4096. Item ids should be above.
