Bluez 5 Set L2CAP Extended Features Mask

I am trying to set my L2CAP extended features mask to enable Unicast Connectionless Data in order to complete Bluetooth Sig certification. I cannot seem to find anywhere to do this. The particular Bluetooth PTS test I am trying to pass is as follows:

TC_CLS_UCD_BV_01_C: Verify that the IUT has the UCD bit set in the L2CAP Extended Features Mask to indicate support for reception of Unicast Connectionless Data...

Does anybody know how to do this?

Thanks