One more thought - not sure about Aspire as I use VCarve, but in VCarve there is a "convert to curves" tool. Letters seem to be created as a series of line segments but you can use the "convert to curves" tool to, presumably, convert to curves... I have just done a quick trial but the CAM post-processor in VCarve itself seems to give straight line segments in the gcode in either case. However, it might be that the dxf written out is different which might help with a different CAM processor.