Thanks to CA Support I am able to do this in VAIM using an autowatcher Template.
Object Class of devTableEntry
Object Attribute to devAllocatedSpace
Set the Instance Criteria Regex like this: \/topdir\/subdir
Set it to the mount pount.
Instance Criteria Match Type to Positive
Threshold Configuration to whatever alarm level you want, with Operator "Equal To", Value 0, Scale 1, Sample Type "Absolute Value".
Under Watcher Settings set the Loss Action to the level of alarm you want.
Then deploy to the server or servers where you need to monitor the mount point.