If I understand correctly your situation, there is not any workaround that I know of.
For instance, you are using an admin install of Office XP professional. Let's say I have 4 seperate templates:
1- installs Word, Excel, and Outlook (everything else turned off)
2- installs Access, Word, Excel, and Outlook (everything else turned off)
3- installs Powerpoint, Word, Excel, and Outlook (everything else turned off)
4- installs everything
If my user had the default install (template 1) and now needs everything...you have to remove the Office install and reinstall with the new install/template.
I was never able to find a workaround for this.