Mapped network drive issue

Hello,

If I have a drive mapped to a network share and then run an application 'as
administrator' the networked drive is not found.
If I use a UNC path rather than the mapped drive letter then the application
is able to work correctly.
If I run the app using the default credentials then the networked drive is
recognised but some apps need to be run 'as administrator' to function
correctly.

Clearly the problem is that applications running as administrator are not
being passed the entire relevant environment from the user account.
With the applications I'm currently running I am able to partially overcome
some of the problems by typing the complete UNC path rather than merely
specifying a drive letter or I can turn off UAC to avoid the need to run as
administrator but that's not the case for all apps.

Is there a permanent workaround to have mapped network drives recognised for
apps which are run 'as administrator' ?

I'm using Vista Ultimate, SP1


Ta