DNxHD with Alpha

Hi

i used to export a Karaoke video with a transparency,

using the DNxHD 36 with alpha. (because it is stills slates with alpha, no quality needed).

now with the CC 2017, all this has changed,

no Avid codec configuration.

no alpha settings. (compressed\uncompressed)

no bit rate recognized.

no depth selector.

etc....

i need a export settings as DNxHD 36.

with alpha channel, compressed, with 32 bit of depth.

ho do i do this?