I haven't found any replacement for IFL files within max. No idea why you call it obsolete. We are trying to use HDRI lighting from hyperfocaldesign.com and the .EXR animation-frames are about 1000-frames long. They are combined in the IFL file.
The format is rather important, you can reverse the direction of the HDRI-animation within the IFL file using Notepad Extra ++
If Corona bitmap doesn't support IFL format, we are stuck with the native 3D Studio Max bitmap mode. There is no replacement, only the "time" addon in the shader itself can help you loop, ping pong or hold the animation when it reaches its final frame.
It's a challange to work with these animated EXR's. Combined they form over 12Gb in data. Would actualy be nice if Corona could lend a hand in dealing with such a data-load.
Grts