I need a API to support changing header/footer of doc, docx, xls, xlsx. I have a huge code written for libreoffice, but the problem is the final document is with broken style and that is a big issue. Similar results are obtained with other open source projects so i am looking for some paid version probably like Aspose but could you give me alternative soltutions as well.
The other aspect of the problem is that i need a convertions from any office document, mail, msg to pdf.
I am looking also for solutions including C# but most probably it will be run under linux so java is preffered.