Question about printing 4cp onto clear

I hope that someone may be able to help me with this (complicated?) question. I posted it originally in another forum on here but maybe this forum would be a better place to ask.

I have a client who wants a clear material printed with a 4 colour photo. However the issue is that the photo must be visible and look the same from both sides of the clear substrate (although reversed obviously).

The problem therefore is that if we simply print a solid white all-over backing underneath the 4cp then from the back-side of the clear substrate all we will see is solid white.

So, what I need to do, if this is possible, is somehow add a 5th colour white dot to the artwork which will define everything that needs to be white in the image (which in 'normal CMYK artwork would be clear and unprinted seeing as the paper itself is the 'white').

We can't really do this by just defining block areas of white. We need to have that white dot incorporated into the overall artwork just like any of the other CMYK colour dots.

Any idea how this can be done and in what software?

Let me say that I am not a printer. I'm an agent and the job is being produced out in the Far East (sorry). My printers don't really understand the artwork issue and so I want to be able to manipulate the client's artwork here and then just send 5 colour artwork (CMYK + white) out to the printer.

Anyone heard of this and know how this is done?

Many thanks in advance

Regards

Rob

I know its way past the time posted but I'm wondering if there was a solution and why couldn't the job be run as a sheetwise with the back side reversed out?