Video Post - exporting from png image sequence to mov file with alpha channel background


Hi everyone!
I’ve been looking for solution for the topic above. I have video sequence in png files with alpha channel. I load them to image input event in Video Post in 3ds Max and than configure image output event with mov file. It renders mov file but without alpha channel in background. I tried with image filter and layer events but it’s too confusing. Couldn’t find any good tutorials in the web.
Can anyone help me with this matter?
Thanks in advance!
I’m working on Max 2013