utl_mail adds CRLF at beginning of varchar2 attachments

Using 10.2.0.3.0 on solaris, I'm trying to write some tests against
utl_mail.send_attach_varchar2.  I receive the email and the
attachments, but the attachment always begins with a leading blank
line.  I've tried varying the att_mime_type but am still having the
same problem.  The leading blank line is preventing applications from
interpreting my RTF text.

Here's the code I'm using.  This example uses RTF, but examples using
straight text have also failed (below)

rtf example:
exec   UTL_MAIL.SEND_ATTACH_VARCHAR2(
         sender => 'xxx@[EMAIL PROTECTED]
'
        ,recipients => 'xxx@[EMAIL PROTECTED]
'
        ,cc => NULL
        ,bcc =>  NULL
        ,subject => 'send_attach_varchar2'
        ,message => 'here is a test of send_attach_varchar2'
        ,mime_type => 'text/plain; charset=us-ascii'
        ,priority => 3
        ,attachment => '{\rtf1\ansi{\fonttbl\f0\fswiss Helvetica;}
\f0\pard This is some {\b bold} text.\par}'
        ,att_inline => TRUE
        ,att_mime_type=>'application/rtf'
        ,att_filename => 'rtftest2.rtf'
    );

plain text example:
exec UTL_MAIL.SEND_ATTACH_VARCHAR2(
sender => 'xxx@[EMAIL PROTECTED]
'
,recipients => 'xxx@[EMAIL PROTECTED]
'
,cc => NULL
,bcc => NULL
,subject => 'scheduled disco mail'
,message => 'Testing testing testing'
,mime_type => 'text/plain; charset=us-ascii'
,priority => 1
,attachment => 'should be in my attachment'
,att_inline => FALSE
,att_mime_type => 'text/plain; charset=us-ascii'
,att_filename => 'neil.txt'
);