Has anyone used a joystick splitter cable - similar to the one found on http://www.dse.co.nz - Cat. no. X2041

I've got 2 analogue gamepads & hooked them up with the splitter cable.
The buttons on the second gamepad don't work. I've added the second controller thgrough Control Panel/Gaming Options, but when calibrating it, the D-pad works fine but no response from the buttons.

I've installed the gamepads on their own & verified that they both work.
The gamepads were switched around on the splitter cable, but whichever one is installed last has no reponse from the buttons.

I've read than Windoze doesn't support 2 gamepads; if that's the case, why do these splitter cables exist?

Using Windoze98.

Any clues appreciated.