you can use Texts and Panels to create something similar to a file dialog
the problem is that is really much work and also not as good as the original ones

here are some functions which may help:
txt_for_dir(text,STRING* name)
txt_sort(TEXT*);
txt_load(TEXT*,STRING* filename)
panel->event
pan_setdigits
pan_setbutton

also oliver2s has created a fully functional file dialog for his IceX3:
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