Can't make transparent BG for black logo with flame effect

[No Frontiers Japan]

So I a mostly-black font logo (same as my profile) that i've added a flame effect to in AE. From enabling transparency grid in AE before rending, I have confirmed that I didn't add any background during the process. Based on this I've got 2 questions.

1. I'm not sure why my animated logos always are automatically imported with a black background in Premiere Pro.

2. Luma key doesn't work because it removes a lot of the black from inside the logo, but I want to keep the black from inside the logo. threshhold/cutoff just mess up the flames, adding a black glow around them. Blend Mode - Screen looks a bit better, but it still removes most of the black as you can see below. So I've got partially the original black... but the 'N' looks exactly the same as the scene behind it. 

Any thoughts on how I can keep my logo black?

[Ann Bens]

If your logo is transparent then yes the background will show as black.

If reality there is no background but just a void which shows as black.

You can turn on the transparency grid in Pro also.

Best is to add the glow in Ae.

[No Frontiers Japan]

Toggling the transparency grid in Pr doesn't prevent my saved burning flame logo MP4 that was (flames added in Ae from an original logo png) from displaying a black background, though.

Not sure what you mean about adding the glow in Ae.

When I import a logo png to Pr it easily shows with no background (even though the file displays the black as a filler).

But once I create an effect in Ae using that same png, and save it as MP4, i can't find a method to bring that into Pr to show without a background.

[No Frontiers Japan]

Here is a pre-render ss from Ae. The black is there. I just want to keep it during my logo reveal (transposed over the night sky shown in first photo)

[Richard M Knight · Accepted solution]

Are you sure your MP4 has a transparency channel?

[No Frontiers Japan]

Was exporting as H.264 so there was no RGB+Alpha channel. Later i'll to switch to Quicktime and see if that solves my issue and post back here.

[No Frontiers Japan]

Fixed. Thanks. I totally forget to switch channels.