Hello,
one trick is to create one triangle with one of the three nodes having a horizontal velocity component of e.g. 0.2 m/s. Have a look in the ASCII *.t3v file, so you can do it manually with a text editor, too. You can shift the element to your desired position with the Shift x/y option.
In the report view of Blue Kenue or in another program you can add a label.
You have to pay attention to the scale in the properties windows.
Hope this helps,
Clemens