How to export with a shadow?

[Will Faulkner]

Hi all. 
this is a 2 part question. 
Im doing product photography, 

I need to cut out the subject and export it with its shadow as a transparent png.

I'll then use the png to create a pattern in PS. 
The 2 issues I'm having is that my shadow layer which has multiply blend mode on it is carrying the white background across to the PNG. 
yhe next issue I have is I can't get the pattern to be transparent and just show the product on top of my chosen background layer, the pattern always seems to have a white layer. Altering the pattern layer blend mode only shows me the product with the shadow including the white behind the shadow. 
does this make sense? Thanks all.

[SJRiegel]

Can you show some screen shots? I am not fully following your process and you intended result. 

[Will Faulkner]

[Will Faulkner]

Nevermind, I found a better way to export the shadow onto a transparent PNG.

[Michael Bullo]

Hi Will. Any chance you could explain the process you used?

By the way, is that a Tim Tam? 🙂

[Jeff Arola]

Something like this?

[Trevor.Dennis]

That works perfectly for me Jeff.  No white fringing and a semi-transparent shadow.  Did you define the lower left outline of the shadow manually?  Only it looks close to spot on, and I am not sure how Photoshop could have worked that out.