With the help of Google (And fmforums.com) i found the solution for my problem
I will post it here so it may be helpfull to others
To make a container field wich opens a embedded pdf file with one click on the file:
Make the container non interactive (layout modus; Optimize for images)
Make a script: (I dont know if I have all the script functions correct because i translated them from Dutch)
Set Variable [$Temp; Value:Get (TemporaryPath)&"Temp.pdf"]
Export [ your container field; "$Temp"; Open Automatically]
Make the field a button which executes the script
This is a solution oft discussed in this forum as well...
If you use insert file with "store a reference" enabled to insert the PDF into a container field, you would also be able to open the PDF file by double clicking the container field. This results in a different appearance in the container field and requires "store a reference", so you may want to keep things as you now have them.