FoxitReaderPortable

Hi,

I use Foxit Reader Portable a lot, from both, PC and flash drive. The user signature created from file or clipboard always disappears when the app is closed. On new start the signature must be re-created. Can someone help as to how to overcom this problem? Which directory the signature pdf should be placed? Is there any menu item or .ini file string to change to prevent loss of signature from the menu ribbon?
Thanks
Laszlo