Al

Two things you can do:

1 The internal "walls" are just the frames for holding the roof structure (as in prototype). You can make one or two easily in HO by making it up from balsa stick, cut and glued, using the original as a template. Remember, it really doesn't carry any weight, it is just a form in the model. Paint as required and presto, a new wall frame.

2 If you have moulding resin handy, just make a mold from one as supplied, using silicon moulding liquid, then cast it up in resin. A quick clean-up and a coat of paint and you won't see the difference.

All the best for the holiday season.

Regards
Michael

Sydney, AUS

Engineering wonders are a thing of beauty - just look at the steam engine