Roger,
From a command prompt on the T610 you should be able to run the following command to automatically add the domain:
xfreerdp -d
This should add the domain to the freerdp connection which will autofill the domain for AD password changes.
Are you using HP Device Manager? I don't think you need it to fix this issue on your sample machine but you could then use it to push out the config on your sample to the units in production.