如何设置页眉页脚距离顶部和底部距离？

#region =页眉=
CT_Hdr m_hdr = new CT_Hdr();
m_hdr.AddNewP().AddNewPPr().AddNewSpacing().lineRule = "-600";
//创建页眉关系
XWPFRelation Hrelation = XWPFRelation.HEADER;
XWPFHeader m_h = (XWPFHeader)doc.CreateRelationship(Hrelation, XWPFFactory.GetInstance(), doc.HeaderList.Count);
//读取图片数据
FileStream picData_ym = null;
string filepath_ym = System.Windows.Forms.Application.StartupPath + @"/Images/ym.png";
picData_ym = new FileStream(filepath_ym, FileMode.Open, FileAccess.Read);
//设置页眉
m_h.SetHeaderFooter(m_hdr);
//页眉插入图片（inline）单位：EMUS，1CM=360000EMUS
m_h.AddPicture(picData_ym, (int)PictureType.PNG, "ym.png", 6200000, 200000);

CT_HdrFtrRef m_HdrFtr = m_SectPr.AddNewHeaderReference();
m_HdrFtr.type = ST_HdrFtr.@default;
m_HdrFtr.id = m_h.GetPackageRelationship().Id;
picData_ym.Close();
#endregion