The ssh service on the WARP is provided by the dropbear application. This service is started on the WARP by the /service/dropbear/run file. The service is started by the last line of that file

exec dropbear -F

If you wish to change the port that the ssh (and subsequently scp) service runs on to make the box more secure, let's say to port 8299 as a random example, you need to change the line as follows

exec dropbear -p 8299 -F

Just change the 8299 to whatever value you wish to use. As the /service/dropbear/run file is in the ramdisk portion of the WARP, you need to make this change to build before you create your images to flash to the WARP.