iTunes deleting apps - driving me crazy

Hello

I have raked other forums for answers to this but cannot find a solution and I am going out of my mind.

I download free apps on my 3G from the app store. Fair enough right?

Then when I plug into the computer to sync my music for iPod use, iTunes decides to disable/erase all the apps that I have tediously downloaded. I do not have wifi at home so now I have to wait till I am next in a wifi place to go through all the download again...

It does this every time... WHY???? HELP????

If you download apps directly onto the phone, the next time you sync up you should've been asked to "transfer purchases" to iTunes. If that didn't happen, then cancel the sync when it starts (or set it to be manual) and then go to Store->Transfer Purchases in iTunes which will copy everything from the phone to your Mac and then you can continue sync'ing the music without losing anything..