I am not sure if you have resolved your problem or not by now, but if you treat the "Speed Camera" locations as general POI's and follow the instructions in the "User Manual" (PDF file on DVD supplied with unit) then all should work fine.
From the supplied "User Manual" PDF file the "Desktop User Manual" (starts at page 111) and the section regarding "Custom POIs" is page 16 of that section (shows as page 126 in PDF in Adobe Reader).