I’m trying to use the same configuration you used with the vx sensor, and I wonder how you wired the sensor with the 3,5 jack.
Here's the wiring that I used - click the photo to enlarge so that you can read the yellow note. I didn't actually modify the VX sensor- it just plugged into the 3.5mm socket and worked. The same connections (with different wire colours) are used within the BeoSystem 3 sensor also. The adaptor that I made was to use the VX sensor with a Passive/Active.
Login to view image
But the lack of IR control may be down to the option settings in the LinkPlayer software. I don't have experience of LinkPlayer but you may find some hints in the following thread where matador had a similar problem: