SecuritySpy Plugin, Set Motion Sensitivity, doesn't work

Hello,

SecuritySpy 3.4.2.
Plugin 1.6.4.
Indigo 6.0.18
OS X 10.9.5

When we make a Trigger or a Schedule with an Action
"Set Motion Sensitivity" to (for example) 60
nothing happens. Only a log text:

28 okt. 2014 09:31:50
Schedule Cam Parking area Sensitivity 60%

But the sensitivity in the SecuritySpy program keeps staying at 40.

What are we doing wrong? Or is it s bug in the Plugin?
(alle other actions with the Plugin (PTZ etc.) are working perfect)

Greetings,

John