Have you found a solution to the configuration problem?
I am experiencing the same issue when I installed Chart FX for Reporting Services and submitted a ticket to the Support team, but I haven't had a response yet. Just as you said, when I tried to open the gauges that had previously been configured to our design specs, they all show as the default config. When I looked at the XML, the <CustomProperties> have an encrypted string value for the properties. The strange thing is that the encrypted value is exactly the same on another computer that has not upgraded and shows the gauges properly. Please help!