When ghostscript combines PDFs, how do I get it to NOT put boxes around links?

I am using ghostscript (gs) from the c开发者_如何学编程ommand line to combine mulitple PDFs into one PDF. It works great, except everywhere one of the PDFs has a link in it, it changes the link from an underscore to a box. There must be some argument I can pass in the call to gs that will get it to use underscores, or just to preserve links as per the original file. Does anyone know how?

Thank you.

Found the answer - use the latest Ghostscript! I was using 8.15.2 before. Just downloaded and built 9.01 and it does not exhibit the problem.