[SeniorAxCons]

В класс ComExcelDocument добавьте

void setMargins(int     _sheetNumber = 1,
                    real    _leftMargin  = 0, real _rightMargin = 0,
                    real    _topMargin   = 0, real _bottomMargin = 0)
{
    COM         comColumns, comWorkSheet, comPageSetup, comColumn;
    COMVariant  comColumnVariant;
    ;

    if (m_comDocument)
    {
        comWorkSheet  = this.getWorkSheet(_sheetNumber);
        comPageSetup  = comWorkSheet.pageSetup();
        comPageSetup.leftMargin(_leftMargin);
        comPageSetup.rightMargin(_rightMargin);
        comPageSetup.topMargin(_topMargin);
        comPageSetup.bottomMargin(_bottomMargin);
    }
}