2.5mm neo to 3.5mm stereo adaptor

[Marcel]

Hey,

I'm desperately looking for a (cheap?) 2.5mm to 3.5mm adaptor to use my normal 
headset with the neo. Does anyone preferably from Europe already have such a 
thing and can confirm it works properly (both stereo channels where they 
ought to be)?

[On irc I was suggested to have a look at pinouts.ru, but they only seem to 
have the pins for the proprietary connectors, not for (eventually) existing 
2.5mm ones.]