hm... i was worried about this... i think we've encountered the same issue that scared me off chiefing a mini-b connector to fit... before mini-b became the absolute standard (also before there was anything handheld that could behave as a usb host) mini-a, mini-b, and the mini-four pin connector (looks like a very small full size B) were all competing to become the standard. I have an old mp3 player with the mini four pin, which is already hard to find in stores. I don't think mini a ever made it off the ground as a client, but the cable on that site is for that use. When a mini host plug was needed they just decided to use a shape that was already defined. What you're looking for is a five pin, not a four pin. The i-river cable i linked to in my other post is listed as a mini host cable, and it's just a pigtail that gives you a full size a female to plug your peripherals into... as soon as devices with full WIMP interfaces get too small for the full size usb A, we'll see companies come out with mini-mice and the like with mini-a males. Fujitsu and sony laptops have already gone to the four pin 1394 female, which is the mini version of "firewire" that you see on DV video cameras.
There seemed to be some confusion over the link to the host pigtail in the other post, so I won't post it here, but it's found over on the iriver site under accessories (picture of headphones), then portable media player (picture of a mpeg playing handheld). it's at the bottom of the screen.