Xilinx Conversion 3.1 --> 6.1

[Max]

Hi all,
i have an old xilinx project developed with version 3.1 (schematic file)
Now i work with Xilinx Project Navigator v.6.1
I'm unable to open it. There is any way to convert schematic from 3.1 to
6.1?

Thank's in advance

Max

Udicom