This wiki page explains details on the setup http://wiki.micasaverde.com/index.php/ExpressControls3in1
As for controlling the timeout, that can be done by changing the variables as described in the wiki page above:
There are also a few custom configuration settings for the sensor for things like Sensitivity, Timeout delay, LED Enabled, Light Threshold, and so on. To set them, click the + button next to the device, choose 'Custom Z-Wave Settings', then 'Add configuration setting', put in the variable number that corresponds to the setting you want to change, choose a data size of '1 byte dec' and enter the desired value, as shown below. Then click 'Save'. Vera will attempt to re-configure the sensor. If it fails, probably because the sensor is asleep, you will see the red cog. Press the blue button on the sensor and you should get a green cog meaning the sensor has been configured with your new settings
Each of the variables are defined in the PDF documentation for the sensor: http://www.expresscontrols.com/pdf/EZMotionOwnerManual.pdf (page 7). The variable number 2 is set to the default value of 20 minutes. (not 30 as some post above indicate).
If the sensor has not seen any motion for a while, and then suddenly sees motion, then a “MOTION” zwave signal is send. Vera will of course receive that. During that the LED on the sensor will light for a brief moment (unless you have programmed the LED not to light up, which you can!).
If no motion is detected for 20 minutes, a “NO MOTION” signal is send 20 minutes later.
If motion is detected anytime within the 20 minutes, the timer is reset, and the sensor will wait with sending the “NO MOTION” signal.
This approach is done to save power as the sensor will run out very quickly of batteries if it is sending “MOTION” commands every time there is any movement.
Now for debugging purposes you may actually want the sensor to talk a lot and send zwave commands on every single movement. You can certainly do that with the sensor by changing the internal variable 5 to any non-zero value. That will consume a LOT of power as the sensor will now send out motion commands on every detected motion. Also in this mode, it will not send out “NO MOTION” commands at all (I have not tried this mode, so I am not 100% sure about this). Be very careful about changing this variable, as it will remain in this mode even after a reset, and it may mess up your routing tables also, as it becomes a transmitter in the mesh network. Thus, after setting the variable back to 0 you must run a “Heal network” in vera, to make sure routing is updated.
Another safer approach is to change the variable 2 (the “on timeout”) to 1. This will make the sensor send a “NO MOTION” after 1 minute of inactivity.
Personally I have experienced mixed results with the HSM100 sensor. In my setup I have not found it 100% reliable. Even when linking it directly with a device, I have seen cases, where either the motion or no-motion command was never received by the light switch located less than 3 feet away. With that kind of issues, you just make it worse by adding a controller in between. I have used it a lot with HomeSeer and recently with Vera.