So in your configuration, the only thing that might be possible is using the GPS itself to rotate the direct-to line about the destination, that is, if your GPS (I don't know much about the AvMaps) has such a way to do this. Some other brands units call this sort of feature "virtual vor" or something similar like that, because it essentially allows you to anchor your destination and treat the direct-to course as a radial by spinning it.
Other configurations, such as an SL30 NAV/COM, or a GNS430 NAV/GPS/COM paired with an HS34, do allow for the HS34's course knob to be used in some circumstances to spin VOR radials or the GPS course line in a "virtual VOR" manner. But this is because those devices are specifically set up to receive course settings from external devices like the HS34. Handheld GPSes do not have the ability to accept courses in this way.