I figured this information would be helpfull. I just made two of these cables. In case you need the pinout info.
HEAD 1 ---------------> HEAD 2 pin 1 blk & 6 gre ----> pin 4 red pin 2 org --------> pin 3 org pin 3 yel --------> pin 2 yel pin 4 red --------> pin 1 blk & 6 gre pin 5 blu --------> pin 5 blu pin 7 brw --------> pin 8 brw pin 8 grey--------> pin 7 grey pin 9 NOT USED
It's a pain in the balls to make. On HEAD 1 you have to split the red wire and put one end on pin 1 and the other on pin 6, and on also on HEAD 1 you have to take the green and black pair and make into one wire and put it in pin 4.
Make sure you use DB9 female heads on both ends. Get the ones that have the RJ45 females on the other side. This way you can connect any size straigh-tru RJ45 patch cord from head to head to accomodate your distance needs...