Problem:

You can define mirrored positions for objects in Format>(Frame): Type, 
Position, Horizontal and align inside or outside. But you can't define mirrored 
spacing in Format>(Frame): Wrap, Spacing.
OOo aligns objects not in respect to object border but to the bounding box 
defined by spacing.
In the attachment both frames are formatted identical (style sheet), but the at 
the second frame the margin ist towards the page margin not the text.

Possible Solutions:
Partial:
Add mirrored to Format>(Frame): Wrap, Spacing

Perfect Solution:
In addition change behaviour of spacing. Margins only towards text, not towards 
page or paragraph boundaries.
Add "from right"/"from outside" to Format>(Frame): Type, Position, Horizontal. 
You don't need the workaround with spacing to align an object right but with a 
margin.