Very tricky sound, headphone, mic problem

OK, now i have a X500 Logitec 5.1 speaker set connected to a ASUS M2N VM DH,

now the speakers are connected though 3 ports, the green one and pink one are no problem, the third plug is into the black port on the motherboard which is also the microphone port.

Now the spearksers work fine, however i recently brought some logitec headphones with a mic , now the mic goes in no problem, however the headphones are a problem.

also iv tested the headphone mic set on 2 ophter laptops and they work fine.

Now as the black headphone port is occupied i got a jack splitter, so i can put to plugs into same port,

Now on the speakers there is a headphone port but its too far away from the motherboard mic port so i cant use that with the mic.

So i tried using the jack splitter in the black port, but for some reason only the side speaker sound comes into the headphone, so i tried using the jack splitter in the green port and the sound was perfect.

Now this is ok, eccept when i insert the mic the rest of the speakers dont turn off automatically like they should, so i have sound in the headphones but also in all the speakers lol,

if anyone would be able to help here it will be much appriciated

thanks