I think there is no option to export ODB++ files from PADS POWERPCB. May be opther in the group can help if this is possible.
But if you need this for Valor FAB verification you can export the ASCII format of your design which valor tool can readin.
of if FAB house can use the IPC356 netlist then you can use the IPC356 netlist extract script files to get the same using menu Tools > Basic scripting. You need to load the file (*.bas) into scripting list.
I usually provide ASCII format to fabhouse which they use for validation.
As others have said, Fablink XE is software from Mentor that works with Expedition and BoardStation RE. I don't think it was designed to work with Pads. I have never used the software, but I have seen demos of it at Mentor's U2U conference and it looked pretty cool. I don't know how much it is, but I am guessing it isn't cheap since it is targeted at their higher end tools. Here is a link to more information about the tool: