[scribus] imposition for 10cm x 10cm brochure printed on A2 printer

[Lars O. Grobe]

Hi List,

I just subscribed, and I have been using Scribus mostly for assembling 
drawings into PDF pages, not much layout so far.

Now I am trying to set up a little brochure. It is 26pages (I will 
insert two blanks at the end to make it divideable by four), should have 
a final size of 10cm x 10cm (so the sheet will be cut to 20cm x 10cm 
which should be fine with A5), and I want to print it on a A2-printer 
without duplex. So print, fold three times to A5, bind, fold, cut.

I have the document in scribus, but now I wonder how do the imposition. 
I found a couple of texts describing brochure making, but they all fold 
only once, make an A5-brochure of A4-sheets.
 Is there a how-to for want I want to do anywhere available? Or even 
some tool doing this? I guess that psbook is somehow prepared for this, 
but I have problems to find out how exactly to use it. Would be great, 
because I could simply convert Scribus' pdf to ps and use the free psutils.

Thank You for help and hints! CU Lars.