Hi
Here's what I did...although this isnt to say that it will work for you - but its worth a try...
1: Download CloneCD, linked from this site.
2: Download unSafeDisc also linked from this site.
3: I used CloneCD to take an image of both the original 'Sims' CD, and also the Living Large/Living It Up CD.
4: Then I wrote the image back to a CD also using CloneCD.
5: I installed the original 'Sims' game from the backup CD.
6: I then installed the 'Living It Large/Living It Up' addon from the backup of that disc.
7: Use unSafeDisc to sort out the Living Large/Living It Up files (in your unSafeDisc directory, copy and paste in the Sims.exe, sims.icd, and dplayerx.dll files. Now run unSafeDisc from this directory, and choose the .icd file from this unSafeDisc dir. It will only take a second and you should get another file called 'testme', rename this to 'Sims' (exactly worded as the original file is (upper case/lowercase too) from the Sims install directory).
I now renamed the original one to something else, and then copy and pasted the new one in.
This is all it took - it did take me a while to get this far mind you, and it was only with the help from a few people that use this forum (thanks guys), only wasted 3 Cd's, which aint bad, time wise it took me about 25 mins to read the image file from each CD, and about the same to write it back to the blank CD.
Hope this helps - drop me an email if you have any problems, or reply here, I'm no expert, but mines working nicely
Oh,and apply the 'nude' patch when you get it working - what a laugh