For some (legacy) applications it may still be necessary to use a fixed drive letter. You can substitute drives to create the drive needed. You can do this by using the Drive Substitutes option.
You can set the drive substitute to be dependent on connection state. For example, when working with a laptop, the mapping should only be set if the user is connected to the network. This means the required state must be on-line connection. If the mapping is not set to be connection state-dependent, it will be set permanently.
The Drive Substitutes feature is found in the Workspace Control Console, under:
Composition > Actions By Type > Files and Folders > Drive Substitutes.
Composition > Actions By Event > At Logon. Select New > Drive and Port Mapping.
Composition > Applications. Open an application and go to Configuration > Actions.