Ok, i got this working now. The key was actually one.dll, so FYI how you can use the Mousewheel for switching VWM's.

;;Modules:
*NetLoadModule One-0.7
*NetLoadModule mzscript-0.8

;;Scripts:
*Script bang !nextVWM
*Script exec !VWMRight
*Script exec !One [DesktopBackgroundClass][][#a][!alert "not found"][.focus][.none]
*Script ~bang

*Script bang !lastVWM
*Script exec !VWMLeft
*Script exec !One [DesktopBackgroundClass][][#a][!alert "not found"][.focus][.none]
*Script ~bang

;;jDesk settings
*jDeskMWheelScroll [.none; !lastVWM; !nextVWM]

;;if you want to select your desk with a hotkey
*Hotkey WIN D !One [DesktopBackgroundClass][][#a][!alert "not found!"][.focus][.none]

Now just klick on your desktop or press the hotkey and you can switch through your vwms, without clicking some tiny buttons :D

Thanks for all the replys. I couldnt use One in the beginning as i couldnt find out the jdesks class or name. So i figured to check out the source and found its class ("DesktopBackgroundClass") there. Rest was easy ;]

PS: "Technically, VWM stands for Virtual Window Manager, but since this module neither manages virtual windows, nor managers actual windows in a virtual way, I don't think that's really appropriate. So let's just say VWM stands for Virtual Desktop Manager, as this does in fact manage virtual desktops. That W in the middle is actually just a D that looks like a W. Ds are sneaky like that, the little freaks. Now go away and stop reading this." ROFL :) I want to use "VD's" everytime i talk about virtual desktops, but i fear noone would understand me ;P But at least RabidCow would ;D