Klaus, When I said we would help you, I meant the boffins on the list -- I'm an idjit :)
You seem to be saying that if you start with a template .svg file that contains (say) "19mm" and "15mm" , when you open the document properties dialog and change *something* (not specified), the dimension of the page, in the svg, change to numbers without units.
If so, (and I could have the wrong end of the stick) and you are using 0.45, I would have to say my experience is not the same. I did this: 1. Opened Ink. Made a 19mm by 15mm document. Drew a square just bcoz. 2. Saved this to mmtest.svg 3. Opened that in an editor. Changed the width and height strings to literally "19mm" and "15mm", form the non-unit numbers that were there. 4. Opened mmtest.svg in ink. Messed with the document - changed backdrop alpha and changed it's default units to mm (which displayed as px). 5. Saved mmtest.svg 6. Opened it in an editor again -- the two sizes were still as in step 3.
(Just in case)TH, /d