Thin pro T520 connection manager RDP always send /multimon parameter

Hi,

I have two screens connected to my thin client and I want to connect to different servers on each screen.  I set up 2 RDP connection in connection manager.  The problem is that the RDP connection manager always passed the /multimon parameter so the connection takes both screen.  There is check box option in the connection manager regarding this parameter.  I want each connection to use only one screen so I can use /monitor to choose the screen (I found that I can pass optionnal parameter from the regstry) .  How can I remove this parameter?  I used the most recent version of FreeRDP  1.1.1-hp14.6 (1.1hp14b-ThinPro-5.2_5.2.1)

Thank you