I make the stage background clear in Animate, publish as an OAM package to place into Captivate and when I test, the background is white instead.
I posted in the Animate community first and someone suggested that I post here instead: Need Animate Clear Background in Captivate
An OAM has to be added with the Media button, HTML animation. You cannot have an animation as background. Slide or master slide backgrounds can be solid colors, graidents, textures or images.
Looks like I totally misunderstood the question. I didn't associate 'clear' with transparency/alpha channel. Strange that this was not solved in the Animate forum...
You need to configure the colour of the OAM background from within Animate before you publish the OAM. You can do this via the Modify > Document settings dialog. You need to set the background to transparent.