background behing glass is darK?

[scoobyboy]

Hi I am having issues when creating glass in vray, when looking through the glass object the background always is darker, not sure why its doing this, I created the glass by using a vraymtl and putting black in the diffuse, refract is white and it has a fresnel reflection. also I cant exclude it from casting shadows from a skylight or hdri.

I have had a search on this forum and cant find anything to help me.

anyone know a solution

thanks

[scoobyboy]

actually just looked again and the dark area is the hdri map, how do I get rif of this?