Car Alarms: Astra 1000 on 98 Navigators, lincoln navigator, ford vehicles

Question
I had a local store install an Astra 1000 on my 98 Lincoln Navigator.  It always works for about 24 hours then the vehicles anti-theft unit keeps it from starting.  They have picked up the vehicle three times now from the locations it died, then re-aligned the chip into the center of the start ring but this is getting really old.  Do you know of any quirks with installing this system on a 98 Navigator?

Answer
The vehicle's anti-theft system keeps it from starting with the key or just the remote start?

A remote start should NEVER keep a vehicle from starting, it should be an add on.  The only thing it should do if there is a problem with it is keep it from starting by remote.  When you do a remote start interface with the Ford vehicles you have to trick the vehicle into believing there is a legitimate key doing the starting.  This is achieved by the use of a bypass module that consumes a key.  This bypass should only be active when using the remote start and not at any other time.  You are saying that the vehicle dies and they have to pick it up, this leads me to believe that the ASTRA is activating the module when it should not be activating, causing the vehicle to see both keys at the same time and not allowing it to start.