ok, I've found a workaround and now it works for me.
- Add a temp partition to your hd.
- Copy F7 iso to this partition.
- Boot from DVD, when loading PATA_VIA driver your dvd rom will be stopped, now think that your PC has only one hd drive and nothing else.
- Point installation to the temp partition and install F7 from the iso you have selected.
- After installation,recompile the kernel and use VIA82CXXX instead of PATA_VIA.