I don't think it's compatible with Maxwell. We would need a way to retrieve the control points from their plug-in, as we do for Max hair (Shave) and Ornatrix/Hairfx. I don't know if hairfarm offers a SDK which we can use, we will contact them about it.
We are also working on a plug-in SDK which will allow 3rd party developers to integrate their custom primitives with the Maxwell exporter. When it's released, hairfarm will be able to add support for Maxwell directly, without any intervention from us. I don't have a release date for this feature yet, currently it's only available in the Maya plug-in.