One plugin:
<add key="AuxVFO-1" value="SDRSharp.AuxVFO.AuxVFOPlugin,SDRSharp.AuxVFO" />

or more:

<add key="AuxVFO-2" value="SDRSharp.AuxVFO.AuxVFOPlugin,SDRSharp.AuxVFO" />
<add key="AuxVFO-3" value="SDRSharp.AuxVFO.AuxVFOPlugin,SDRSharp.AuxVFO" />    
<add key="AuxVFO-4" value="SDRSharp.AuxVFO.AuxVFOPlugin,SDRSharp.AuxVFO" />
<add key="AuxVFO-5" value="SDRSharp.AuxVFO.AuxVFOPlugin,SDRSharp.AuxVFO" />
<add key="AuxVFO-6" value="SDRSharp.AuxVFO.AuxVFOPlugin,SDRSharp.AuxVFO" />    
<add key="AuxVFO-7" value="SDRSharp.AuxVFO.AuxVFOPlugin,SDRSharp.AuxVFO" />
<add key="AuxVFO-8" value="SDRSharp.AuxVFO.AuxVFOPlugin,SDRSharp.AuxVFO" />
