Silicone Grease is supposed to be the business for this, at work we use Rocol Sapphire for all our rubber seals etc, It can be bought from Enco Industrial supplies
Edit: Or Trade Tools - http://tradetools.co.nz/products/2845260
Here's a couple of pics of my swb Paj, Winch bumper just finished hoping to install and wire up winch this week.
http://imageshack.us/photo/my-images/20 ... 655tt.jpg/
http://imageshack.us/photo/my-images/7/dsc01656a.jpg/