How can I backup my apps from the iPad to my mac? I recently updated to Lion and didn't keep any backup of the local library for my installed apps on the iPad.

Now when I'm trying to update to the latest version of iOS it tells me this:



But when I'm trying to Sync Apps it tells me this:



The thing is that I don't have any apps right now in my iTunes library and my question is: How can I backup my existing apps from my iPad without losing them? 

I really want to avoid downloading them all again, since some of the apps (like VLC) are not even in the AppStore anymore and I don't want to jailbreak it.
First, you should authorize your computer with your iPad if you haven't already. 


From the Store menu, choose Authorize Computer.
In the dialog that appears, the Apple ID button is selected by default. If you have an  AOL account, select AOL.
Enter your Apple ID or AOL screen name and password, then click the Authorize button.


Then, transfer your purchases: 

From the File menu, choose "Transfer Purchases from "Lipis' iPad" "

Wait for iTunes to complete the transfer. 

Check in your library for your apps and the like.

Then you can sync without worry.