Mikro,
Mikro Trekker wrote:
PdfPKCS7 pk7 = new PdfPKCS7(null, chain, null, "SHA1", false);
The final parameter of the constructor, the boolean hasRSAdata, is documented in the method Javadoc as "<CODE>true</CODE> if the sub-filter is adbe.pkcs7.sha1". Isn't that your sub-filter of choice? Could that "false" be the problem?
As I only have the iText Java sources here, not the C# source, I'm not completely sure if this comment is valid for your situation, though.
Regards, Michael.