LaserSoft Imaging

I have 2 different Silverfast 6 licenses for 2 different Microtek Scanners (SM 4 & Artixscan 4000).
How can I have BOTH Photoshop-Plugins or both TWAIN modules installed the same time on the same PC?
One installation overwrites the other, all settings get lost.
By the way - thank you for the kind offer of getting absolutely NO discount for the 2nd license.

Dear mh1030 -
Please install first one version ( ScanMaker 4 ) and move the plug-in and the SilverFast folder out of the Import/ Export folder into the folder: Plug-Ins and then install the second version. One version is in the Import / Export folder and the other in the folder : Plug- Ins
Now you can work with both versions and your settings will not get lost

with regards

Christoph