DS wears Piedros, and has since he has been walking.
Do you see a physio? they are often very good at suggesting strategies for this sort of thing.
Tsome of the things she suggested to us for a similiar issue (needeing to get DS to stand on tip-toe regularly), could you:
Place a snack that she really likes, at snack time, on a coffee table at the far end of the sofa - to encourage her to cruise along the sofa?
Take her to the park in them and get her to cruise up the slope to the slide (if they have things like those slides which have a ramp up to a bridge rather than steps), and encourage her to hold on to the railings as she goes?
Always place her toys - or things which arouse her curiosity - a cruise-trip away?
Gently roll a ball away from her.
I would guess she needs to get used to the sensation of walking in them. My cousin's grandchild wears Piedros for the same condition as your dd, and they have REALLY helped him to gain stability and confidence, so do persist.
were you shown a catalogue? depending on what structure she needs, there are lighter models than the 'hiking boot' style - sude trainer-y ones which are lighter. Have a look next time if you think the weight is an issue - but building up her muscles would perhaps be a good thing?