FPS Weapon Lighting Conundrum!

Hello, I recently followed the steps for first person weapon models found here

http://unity3d.com/support/documentation/Manual/Cameras.html

However when rendering with a separate camera none of the shadow information from the intital render pass is included, this means when I walk inside of a building or a shadow of a building, the view model continues to be lit as if it were in the sun, this makes it look very odd, As the cameras are in the exact same position, is there any way to share the depth texture for that light in a seperate pass?

Abandoning that, can anyone think of any way to get the weapon not to clip without a seperate camera? I liked the idea of using a seperate camera as I can control the weapon's fov to make it look correct,

Any help would be much appreciated