Sure thing, Chief...
I'm basing this of using Google Chrome. IE or Firefox shouldn't be too different. Log in to https://www.arcgis.com. Click on the green padlock icon in the address bar, then the connection tab in the window that pops up. There should be a link there for certificate information. Open it up. A new window will open. Click on the tab that reads Certification Path. Select the certificate at the top of the chain - that's the Root CA certificate you're missing. Double click on it, go to the Details tab, then click the button that reads Copy To File. Save it someplace you'll remember.
Now, you need to get that file onto your Topcon device. I just used a SD card to copy it over. My Topcon's out in the field right now, so I have to go on memory for this next part. In the Windows Mobile control panel/settings window, there's an option for certificates. Open that, then find where to import a new one. Point it at the file you copied over & it should automatically set it as a Root CA.
That's it. If you're still having issues, let me know & I'll get back to you once the device is in hand again.
