Very sophisticated and expensive software may do it, but you'd better get 2 free things: a pdf printer (like PDF Creator or CutePDF), and software that allows you to combine several pdf's into one. I downloaded PDF Rider from Softonic. (Make sure you do not accidentally download junk they want to push on you as well).
The procedure is very simple, though it looks long. First you transform the single S-89 to proper A6 size paper. Then you combine 4 of these new forms into one 4 page document with A6 size paper. Then put that 4 page document 2x2 on A4.
Open the single S-89 that you get from the branch as you normally would. Print, and choose your pdf printer here! Make sure you choose output paper size A6. Do not scale! i.e. print at 100% size. Give it a name you remember, like S-89 A6.pdf
Open the new pdf in pdf rider. You may need to rightclick and use Open with...
In the Tools menu, choose Insert page. Navigate to the same file you already opened and choose that one. Repeat 2 more times. So you opened the file one time and added it 3 times. Depending on Settings, the resulting files may not be properly shown, but they will be there. Choose Save as, and save as S-89 4A6. This is your 4-page document, all A6 pages.
Open that final result in your regular pdf reader. Now print to pdf again. This time make sure the output is on A4, and you choose multiple pages per sheet. If necessary, manually adapt the number of pages per sheet to 2 x 2. Choose S-89_mu as output name. Certainly here in the final result you will want to include the language code. So S-89_mu-E.pdf for English.
Next: go to the pdf2jpg.net website to transform that last pdf you made to jpg. Make sure you choose Excellent Quality 300dpi. When you download that jpg file, it will have -page-001 in its name. Make sure to delete that, so the file name matches the one that the branch provides. If you don't, TB won't recognise it as an assignment slip. Move that jpg into the template folder. TB will attempt to understand it once you actually choose it, and usually that works pretty well. ;-)
For accessing the database my personal preference is http://sqlitebrowser.org/
For editing templates I now use https://code.visualstudio.com/