Need to bake my maya material?

[Traggey]

The reason why you shouldn't use JPG is partially because of quality, but mostly because game engines are simply not built to use jpg files. Many use DDS textures because of the compression settings, making the textures more suited for gameplay use, rendering lower quality verisions the farther away from it you are for example, also know as mipmapping. With JPG, you don't get any mipmapping.

As for the UV channel thing, when you create a UV map, there are different channels for it. For example Unreal engine uses channel 1 for textures, and channel 2 for shadow maps.

You might have just accidentaly put the UV map on the second UV channel instead of the first, HPL does not use channel 2 and that would result in your old bad UV's being imported instead.