Can't take calls with "headset" button of a phone, when using wireless headsets

For "wireless" headsets pressing the headset button on the Deskphone first does NOT automatically activates the call control button on the headset. Meaning that if the user prefers to use the headset button on the Deskphone instead of the call control bottom on the headset to answer or to originate calls the call control button on the headset has to be active. Once the call control button on the headset is activated (by pressing it) the headset button on the Deskphone can be use to make or to receive calls, without it being active the headset will not receive audio.
 
Note that the above is common with wireless headset in general. We tested the Sennheiser CEHS-AV 03 Adapter and DW Pro1 wireless headset, also the Jabra LINK 14201-33 Adapter and Pro 920 wireless headset with Avaya 1600 and 9600 Series Deskphones with the same results. The Application Notes fails to mention this limitation (in Section 6).
 
Following are the instructions we provided for Jabra wireless headsets solutions I tested, the same applies to Sennheiser wireless headset products:
 
To Answer a Call :

•  Press the call control button on the headset to answer an incoming call.  This would automatically activate the headset button on the telephone. 
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•  Alternatively, if the headset button on the telephone is pressed first, then press the call control button on the headset, if it isn't already activated, to answer an incoming call.  Note that when answering a call, pressing the headset button on the telephone does not automatically activate the call control button on the headset."