The Termcfg.bin file includes the Emulation Parameters that are configured for TelnetCE. You likely copied those properly from one device to another via the approach that you used.
There is an easier method however. From within TelnetCE on a device you can navigate to Term->Configure->Import/Export settings. If you select the option to Save all settings to a file all of the settings that you have made in TelnetCE on the one device will be exported into a WLTNA that you can import into the other device via the same Import/Export Menu. The password to enter the Import/Export menu is "system"
If you have difficulty exporting the WLTNA, or that is not an option in the version of TelnetCE that you are using, you can copy the config files in the directory that you were exploring, but you will also want to include the Hostcfgs and S24.dat files. These will be copied into the Application directory as you have mentioned but they will not actually be merged into and made available in TelnetCE on the device until after it has then been rebooted.
Thanx for your help. My version hasn't any export-option but I copied all files from the \application\wavelink folder and it works :-)