At last...I solved it.I used Unico Dual Plus ... (UNICO DUAL PLUS is a new SW commands interface able to control aftermarket radios, by managing both Canbus, K-bus and resistive protocols)
http://www.paser.it/product_info.php?products_id=80
I can use volume +/-,seek +/-,mute,track +/-,change mod(am,fm,cd,ipod etc.),forward,backward these are what i need.