Sorting problem

Hi all,
I have a problem sorting varchar fields.
I will explain the problem with a simple example:

this query  select '##10' as sortfield  union  select '###1' as sortfield  order by sortfield
produces this correct output:  '###1'  '##10'

but this one
 select '##10############--------####79909999' as sortfield union select '###1############--------####79909999' as
sortfieldorder by sortfield
 
produces this wrong output:  '##10############--------####79909999'  '###1############--------####79909999'

I'm using postgresql 7.4.3 on Suse Linux 9.1.
I created my db using: initdb --pgdata=../data/ --encoding=LATIN1
--lc-collate=it_IT --lc-ctype=it_IT

Any suggestion?
Tia
Ruggero