John.D.Casey@mail.sprint.com has written a task calles ifTask that can help you.
You can find that at the following URL:
Hope it helps
From: Jon Skeet [mailto:firstname.lastname@example.org]
Sent: Wednesday, June 13, 2001 3:16 PM
Subject: RE: Conditional task execution
>> Is it possible to execute a task only if a property has a
>> specific value?
> You'll be wanting to read that very nice manual and look at
> the if/unless parameters to the target task.
... and then come back and say, "No, that doesn't actually do what I
if/unless specify whether or not to execute a task if a property is set
*at all*, not if a property has a specific value.