There are several commands in the global.lua file.
Open the file in notepad and search for volume.
Then you can alter the script you use and add the command in and set your volume.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit, Screen resolution 1680 x 1050.