This is the code we use for it. Now the problem is, everytime we debug it, the panel starts at the very left side of the screen. It doesn't matter what value we assign to set the left border of the panel, it will always start at the very left side of the screen.
Guys, I found the answer, the module SlidingPanels adjusts the position of the panels, that's why it is always placed to the left side.
If you want to change it you'll have to change the position in the module itself.