DominoPDF supports PDF/A-1b with an independent color space.
To enable support for PDF/A-1b in DominoPDF, simply pass the PDFACompatible=True setting in your DoPDF() call.
Call DoPDF(sInput, sOutput, "PDFACompatible=True")
DominoPDF is unable to support PDF/A-1a for a number of reasons;
The file must contain 'tagged' textual data in order to recover the text information easily.
This is simply impossible for a general purpose PDF converter.
In the general case there is no way to infer which portions of text on a page are (for example) running heads, page numbers, footnote rules etc.
Nor is it possible to reliably generate, for example, the reading order of the text.
The ISO specification clearly says "PDF/A-1 writers should not add structural or semantic information that is not explicitly or implicitly present in the source material solely for the purpose of achieving conformance." and also "It is inadvisable for writers to generate structural or semantic information using automated processes without appropriate verification."
Although we could produce a document which would pass an automated conformance checker, we could not guarantee that the file would be 'correct' as regards the intention of the specification.