Thank you Stevie G this works perfectly. My apologies for not explaining fully...
If as\selected = True
angle = DELTAroll#(camera,as\mesh)
drawimage3d(arrow,0,0,0,-angle)
EndIf
If as\selected = True
angle = DELTAroll#(camera,as\mesh)
drawimage3d(arrow,0,0,0,-angle)
EndIf