I have the sunplus 536 (with the camera) it looks about the same. It came with a little cd full of buggy software, most of them refused to install. For flashing or updating the firmware (i assume) there came this tool. I'm pretty interested in playing with mine too but I had no idea how to use this program. I can email it to you if you want, but I think it's a little flawed. (pressing ver. check fails. as does all the other 5 buttons that come with it.)

But since some of the other software on that cd could be found on the net try looking for ISP_V5.2.exe (the name of the program, which comes with a few .bin files in the folder)

the folder on the cd was called (assumedlyt the date of the firmware):
isp_v5[1].2_200441229

keep me posted.