I'm learning how to create simple walls in TSRW by replacing the overlay file of an existing wall with a custom picture. I change the title and description of the original wall in TSRW and TSRW displays the new info, but in game only the original title and description show up with my walls. Can anyone help me figure this out?

Hmm I don't think I've come across this problem myself so I don't have suggestions off the top of my head, but if this problem is still unsolved, do you have a .package (or sims3pack) I can download and take a look at to see if I can figure out the problem/fix it/provide any semblance of useful information back to you? Also what the original title/description are vs. what you want it to say, so I'd know which version of the title/description I'd be seeing in each case.

I remember I came across the same issue when I was making walls with the updated version of TSRW. I switched to an older version and it was resolved. You can find the older versions of TSRW (the ones before TS4) here.