[scribus] how to save non breaking spaces

[Pascal GRAFF]

Hi,
I'm using scribus 1.4.3 on a Mac (OS X 10.7.5).
In order to reduice the size of non-breaking spaces before glyphs like '
: ? ! ; ', I reduice the size of their font to the third. Everything is
going fine, and I'm able to export the result in a  correct pdf file.
The trouble is that, after having saved the ***.sla file, if I try to
re-use it, opening it once more, all the changes of size of the
non-breaking spaces are lost.
Is there any turn-around to prevent it ?
Thank's in advance for any advise.
Pascal