The vlan.dat files are not copied into the shadow directory. They are binary files which are unreadable by humans.
But in the file system (\CSCOpx\files\archive\config) you would
see something like this:
20051028161009running.cfg
20051028161009vlan.cfg
20051028161707running.cfg
20051028161707vlan.cfg
If you have five generations of running configs archived, the version numbers for running
and vlan.dat will be matched. So if you want to restore version 4 of the running config,
you would restore version 4 of the vlan config.
You need to use the CLI to restore the vlan and here is the command:
cwconfig put -u username -p password -device device_name ?version version_number -filetype vlan
You have to reboot the device after downloading the VLAN configuration. Only after you reboot the device, will the VLAN configuration take effect.