Exported *.png images seem to have black background when it should be transparent

[HarryPutnam]

Running Designer pro 6.1.2.13287 on Windows 7 Home Premium

I'm probably bumbling around and buggering up the export of png formatted images, but it appears something besides transparency is getting exported as backbround.

In the screen shot inlined below you see the artwork inside a xara document ready for exporting.



I do `Select all' then export to png.
The poorly drawn green arrows were added in photoshop to show the area I'm talking about. The xara document which is apparently also getting exported in some way.

At least certain other tools see a black background in that area. Not all tools have that problem with the image. For example; photoshop sees only transparency there.

But when I browse the exported *.png files with `Epson print CD', it sees black in that area as illustrated by the screen grab below:



The first two images look clean as expected (I'll explain in a moment) but the third (the one that hasn't been cleaned in Photoshop) shows the black background in that area.

The first two were cleaned up in photoshop and now appear clean as expected.

So to get a usable image for import into Epson's tool I must:

1) Export as PNG from Xara

2) Open with Photoshop and run thru a procedure where anything outside the outer blue ring in the image is deleted.

(Even though PS only sees transparency, if I select everything from the blue ring outward and delete it, saving back to png, then Epson's tool sees transparency there)

3) Import into `Epson Print CD' and print the graphic to a printable DVD.

How can I skip the second step? That is, how can I get a clean export in step one? What is it that some tools are seeing as black background?