You can download the ViconGPMaya plug-in from the Vicon Online Support website.
When you install the file, please check the path to Maya folder for plug-in.
Install the plug-in in the usual way form Windows->Settings and Preferances->Plug-in Manager (ViconGPMaya should appear in this list) Type "ViconGPMaya" at the command line to run the plugin and click Enter of tenkey.
First you need to import the vsk. Click VSK in the list and browse for the subject file. Next you need to import the V-file. Click the V-file option in the list and browse for a v-file that has the subjects motion data.
Finally click the "All" button. This will import the VSK and v-file data in the your scene. If your scene have no animation, vsk file may be different.
This plug-in support the other format, so you can import many file formats. Please use it.