first page header not working

[victorrwangrinan]

header is ok, but first page header is not working, I have to check "different first page" when opening it in Word every time, Can anybody help?

p.MsoFooter,
li.MsoFooter,
div.MsoFooter {
margin: 0;
margin-bottom: .0001pt;
mso-pagination: widow-orphan;
tab-stops: center 3.0in right 6.0in
}

  @page Main {
      margin: .5in .5in .5in .5in;
      mso-header-margin: 0cm;
      mso-title-page: yes;
      mso-header: header;
      mso-first-header: firstHeader;
      mso-footer: footer;
      mso-footer-margin: .5in;
      mso-paper-source: 0
  }

  div.Main {
      page: Main
  }

[victorrwangrinan]

is there any idea?

[starsoul666]

how to set header work?