symbologyname for scanned barcode?

i am using honeywell sl42 sled,i have included captuvo.dll to my app,able to fire follwing events getting rawdata for the scanned barcode
[Export("captuvoConnected")]
public void CaptuvoConnected()
{
}
[Export("captuvoDisconnected")]
public void CaptuvoDisconnected()
{
}
[Export("decoderRawDataReceived:")]
public void DecoderRawDataReceived(Foundation.NSData data)
{
}

But unable to get symbology name using below code,but this event is not getting fired
[Export("SymbologyName:")]
public string SymbologyName(Symbology symbologyname)
{
}

Thanks,
vijay