Tricky reverse issue

I need some help with a reverse problem.
I have a mc with 37 frames with stop on frame 1, 19 and 37 and should be controlled by 2 buttons.
On one button I have the following code.

on (release)
{
if (_root.bmw360._currentframe == 1) {
_root.bmw360.gotoAndPlay(“2”);
}else if (_root.bmw360._currentframe == 19) {
_root.bmw360.gotoAndPlay(20);}
}

Now i need som code on button 2 that plays it backwards.

ie
on (release)
{
if (_root.bmw360._currentframe == 19) {
_root.bmw360. [COLOR=“Red”]play backwards from 18 to[/COLOR] (“1”);
}else if (_root.bmw360._currentframe == 37) {
_root.bmw360. [COLOR="#ff0000"]play backwards from 36 to[/COLOR] (19);}
}

I dont think that the above code is right at all but it tells how I want it to function.

I tried another really great code for reverse found here but that didnt worked right for this problem, or does it?
So please can someone help me with this?