Unusual HDMI resolution (864*480/854*480) possible with ADV7513?

I would like to connect an 18 bit digital RGB output (LCD connector) of a video generation device to a display device which requires HDMI input.

The display device strictly requires an input resolution of 864*480 (DV NTSC Widescreen) or 854*480 (FWVGA) because of hardware limitations of the display (no configuration possible). I am able to set digital RGB output to this resolution, but converting into an HDMI signal of similar resolution seems to be difficult .

What I require is a converter board supporting such unusual HDMI output resolutions. Does Analogue Devices ADV7513 (or similar) have such function?