We use signature files (Tools/options/Environment ) to add all our signatures and disclaimers. This is server-based so it doesn't matter what computer you are logged onto when you are using GW. This is what I use in my disclaimer AFTER my regular signature:
CONFIDENTIALITY NOTICE:
This is a transmission from the XXXXXX Company and may contain information which is confidential and proprietary.
If you are not the addressee, any disclosure, copying, distribution,or use of the contents of this message is expressly prohibited. If you have received this transmission in error, please destroy it and notify us immediately at 111-555-1111, x111.