se metto:
ooo.exe=/usr/lib/libreoffice/program/soffice.bin
ooo.enabled=true
ooo.port=8105
jodconverter.officeHome=/usr/lib/libreoffice
jodconverter.portNumbers=2022,2023,2024
jodconverter.enabled=true
ed elimino lo oo_start.sh (cioe' non lo faccio partire a mano)
comunque vedo 
ps aux | grep soffice.bin
alfresco  9137  2.5  0.5 523068 47104 pts/2    Sl   11:37   0:00 /usr/lib/libreoffice/program/soffice.bin –accept=socket,host=127.0.0.1,port=8105;urp;StarOffice.ServiceManager -env:UserInstallation=file:///opt/alfresco/alf_data/oouser –headless –nocrashreport –nofirststartwizard –nologo –norestore
cioe' mi sembra che se ne freghi di quello che metto in jodconverter ecc..
comunque in questo modo le conversioni le fa, sono pero ritornato al problema delle immagini 'nere' nel thumb.
nei log vedo:
—————
10:53:31,733 DEBUG [org.alfresco.repo.content.transform.TransformerDebug] 894.1.1.1.2   pdf  jpg  <<TemporaryFile>> 67.8 KB transformer.complex.PDF.Image<<Failover>>
10:53:31,734 DEBUG [org.alfresco.repo.content.transform.TransformerDebug] 894.1.1.1.2.1 pdf  jpg  <<TemporaryFile>> 67.8 KB transformer.ImageMagick<<Proxy>>
10:53:31,735 DEBUG [org.alfresco.repo.content.transform.TransformerDebug] 894.1.1.1.2.1           Failed 06190982 Unsuported transformation attempted
10:53:31,736 DEBUG [org.alfresco.repo.content.transform.TransformerDebug] 894.1.1.1.2.2 pdf  jpg  <<TemporaryFile>> 67.8 KB transformer.double.ImageMagick<<Complex>>
10:53:31,736 DEBUG [org.alfresco.repo.content.transform.TransformerDebug] 894.1.1.1.2.2.1pdf  png  <<TemporaryFile>> 67.8 KB transformer.ImageMagick<<Proxy>>
.
.
.
0:53:32,953 DEBUG [org.alfresco.util.exec.RuntimeExec] Execution result:
   os:         Linux
   command:    /usr/bin/convert /opt/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_source_7062188067923673474.pdf[0] -auto-orient -resize "100x100>" /opt/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_target_2353618930893456806.png
   succeeded:  true
   exit code:  0
   out:
   err:
10:53:32,957 DEBUG [org.alfresco.repo.content.transform.TransformerDebug] 894.1.1.1.2.2.2png  jpg  <<TemporaryFile>> 5.9 KB transformer.ImageMagick<<Proxy>>
10:53:32,981 DEBUG [org.alfresco.util.exec.RuntimeExec] Execution result:
   os:         Linux
   command:    /usr/bin/convert /opt/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_source_4242382844207685158.png[0] -auto-orient -resize "100x100>" /opt/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_target_4056540275020531686.jpg
   succeeded:  true
   exit code:  0
   out:
   err:
10:53:32,983 DEBUG [org.alfresco.repo.content.transform.TransformerDebug] 894.1.2       jpg  png  <<TemporaryFile>> 2.7 KB transformer.ImageMagick<<Proxy>>
10:53:33,003 DEBUG [org.alfresco.util.exec.RuntimeExec] Execution result:
   os:         Linux
   command:    /usr/bin/convert /opt/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_source_8881506912096393765.jpg[0] -auto-orient -resize "100x100>" /opt/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_target_4494862132639251753.png
   succeeded:  true
   exit code:  0
   out:
—————