Exporting transparent PNGs (again)

[Chris Carroll-Davis]

Hello again folks.

I recently posted a question about Rev's weird behaviour when  
exporting transparent PNGs from fields with Japanese text.  No-one  
(understandably) was able to offer any help so, as is often the case,  
I think I'll be looking for a workaround...

... Exporting non-transparent PNGs works fine so, in theory, should I  
not be able to export the image (perhaps to clipboard or variable)  
then apply this to a graphic as an alpha channel?  Then export the  
resulting image as transparent PNG?

So... two questions:
   1)  Does the above workaround solution sound feasible?
   2)  How the devil do I do it???!!

I've had a few half-hearted attempts at using the alphadata property,  
but I can't get it to work at all!  Can anyone point me to some  
example stacks that use this property that I can dissect?

I'd be grateful for any suggestions!!


Chris