Currently we only have an upwards going saw lfo to choose from ( and other waveforms offcourse) ,and because we can’t set the modulation amount to a negative there is no possibility to create a downwards saw lfo .
WHat about extending the range of the modulation amount ( couple of octaves or so ) ?
I can’t verify now, but this should work as a workaround:
set LFO destination to the input of an Hydra device, then set an hydra output’s range to 100%-0% in order to reverse the saw, then set the output of the hydra to the parameter you want to automate.
a bit awkward, I know 
I mean the lfo’s in the instruments/envelope window 
( not the metadevice lfo )
The instrument/envelope lfo’s only have an upward saw shape.
Your solution is all fine etc…except for the fact that you can’t modulate ( a sample’s )pitch with a metadevice 