iPhone 3GS doesn't want to Sync with MacBook Pro

I have the 3GS, it is jailbroken, it has 3.1.2 and every time I connect it with the original USB cable to the MacBook Pro in Mac OS X it doesn't want to Sync. The system doesn't even make the sound for a newly connected device, nothing happens. It doesn't even show the photos, and in iTunes it doesn't show the phone.
But on the screen of the phone it says that it is charging.
I want to connect it to the computer and sync it with the songs I got and I just want to put some music in it and to update it!
Every time I plug it in my Windows part(because my laptop has Boot Camp, I am also using Windows 7) it always shows the phone, it can sync it and it shows it on iTunes and wants to put the photos in the computer, but all the music, files, contacts and etc. is on my Mac, so I need to make it Sync with the Mac.
Please help me out! Thank you!

Raptole said:

I have the 3GS, it is jailbroken,

Click to expand...

Nuff said. Restore it and see what happens. You broke it, it's your problem.

Also, that line pretty much made your thread off limits, talking about JB devices is frowned upon here.

Well said, and we're done here.