aspdbq,
I personally have never used the pdfsharp library, and obviously, we cannot provide support for it, nor guarantee it's compatibility with our software.
That said, I would invite you to check out the "Merge PDF" action of PlanetPress that allows you to merge multiple pdf files together. Here's a link to the documentation:
http://help.objectiflune.com/en/planetpress-workflow-user-guide/Default_CSH.html#/6296.htmlYou could also simply use a Send to Folder output and check the "Concatenate files" option, which works with PDF files. All you have to do is make sure the file name is always the same, and instead of overwriting the file, it will concatenate them.
Should you need a more advanced solution, we have our PDF API that can be used in scripts through the Run Script action. It contains all sort of functions to handle the manipulation of PDF files, whether it's concatenation, extraction, optimization, etc... Here's a link to the documentation on it:
http://help.objectiflune.com/files/EN/alambicedit-api/AlambicEdit.htmlAll of these options are built-in options to do pdf concatenation, and will be much more compatible with the pdf files generated with our software. I would suggest that you give these options a try, and see if they work better.
Regards,
Raphaël Lalonde-Lefebvre