os2l command for on/off and flash buttons in Live

The os2l command button is working great in Virtual DJ & ShowXpress. For example I'm sending the command os2l_button "Blue #7" and the button turns on in showxpress. How do I send a command to turn that same button off?
And if I want to control a flash button in ShowXpress, how do I do that? I want to send a command to hold down a button, then release it during a certain part of the song. What is the command for that?
Thank you
And if I want to control a flash button in ShowXpress, how do I do that? I want to send a command to hold down a button, then release it during a certain part of the song. What is the command for that?
Thank you