Lol I think that's your Google voice number, well that's where my Google voice number shows.
You should be able to start a new conversation and reply to received texts. If you have a text plan with your mobile number, send test messages to google voice from it or vice versa. That's how I did it.
Sent from my SGH-I997
I did buti'm only given the option to start conversations when using it on the computer
Sent from my SAMSUNG-SGH-I997 using xda premium