Take a look at the profile.c file in the 'Include' folder. Also search for 'profile.c' in the manual. There are several plots that you can call from that file that don't use a time-based x axis. Based on that, it should be possible to plot what you want.

Also, I understand that the graphics package that comes bundled with R and is now accessible by Zorro's R bridge is quite high-powered and would most likely provide a solution. I haven't used the R bridge yet so can't tell you more than that.