How can I print borderless on a custom paper size?

I have an HP 6500A Plus, and it should be capable of printing edge to edge, even on custom sizes. After contacting both Apple (I am running MacOS 10.8 Mountain Lion) and HP for answers, I burned a lot of time with Adobe either just plain not getting an answer because I didn't buy it or being given the run-around. I need to know what Photoshop is doing to block the available capabilities from working.



Thanks!

Hi uniqueart,
This isn't an Adobe issue; if you're unable to print borderless then it has to do with either your printer's capabilities or your printer's drivers. For custom sized paper, remember to un-check "Scale to fit paper size" under the Paper Handling drop-down menu in your printer options.