Alpha channel render

at first sorry for my English.
I want to render simple packshot. I am rendering png with transparent bg. I want to keep reflection, but i dont want to keep material in which is this reflection.
Her is link to photo which is more clear to understand what i want:
1 foto - is what i have now
2 foto - is what i want to have…
I hope you understend me… :slight_smile:
And thx for help.