I was searching in the web for a single way to use the Artcam`s toolpaths in Estlcam, but i found nothing. so i have to get in the ring and try it by myself. i don´t really know if this is a common knowledge in the community, but i find an easy way to do it. its really easy, you only have to save the toolpaths in the Artcam with the postprocesor called G-CODE (mm).tap (i guess if you select the option in inches, should be the same, but with inches like unit). then you have to rename the toolpath file to a *.nc extension (just press F2 on Windows and change the extension). now you have a compatible G-Code program ready to run with estlcam as CNC Controller.
i hope that somebody can understand my poor english.