I use biz2006 + rosettaNet as our EDI solution. Now I meet a issue that, when a partner send pip to us, the content(base64 encoded) could not been converted to XML plain text.

Here're content of the pip we received.

MIME-Version: 1.0
Content-Type: application/xml; charset="UTF-8"; RNSubType=service-header`
Content-Transfer-Encoding: base64
Content-ID: 3e10e7db96b84cafbee51e66e020729f
Content-Description: body
Content-Disposition: attachment; filename="Attachment1"
PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0idXRmLTgiPz48IURPQ1RZUEUgU2VydmljZUhl
...==

I find a working format as below

Content-Transfer-Encoding: binary
<?xml version="1.0" encoding="UTF-8"?>

Anyone could tell we how to solve the issue?
Any suggestion is appreciated.
Thanks.