Add a new graph type to "graph twoway"

I wrote a simple program called tsline2 that plots a tsline and formats the graph in a certain way (white background, yline at zero etc). The program works ok. However, I cant combine in with other built-in graphs via "twoway" command.

twoway (tsline2 y) scatter (z time)

gives an error: r(198) tsline2 is not a twoway plot type.

tsline2 y works just fine.

Is there any way to integrate the tsline2 command into the twoway structure?