vml渐变:怎么让group 容器实现渐变

Question

怎么让下面的group 容器实现渐变<v:group ID="group1" style="WIDTH:700px;HEIGHT:500px" coordsize="4900,3500">
  <v:line from="200,100" to="200,2700" style="Z-INDEX:8;POSITION:absolute" strokeweight="1pt">
    <v:stroke StartArrow="classic"/>
  </v:line>
  <v:line from="200,2700" to="4500,2700" style="Z-INDEX:8;POSITION:absolute" strokeweight="1pt">
    <v:stroke EndArrow="classic"/>
  </v:line>
  <v:rect style="WIDTH:4600px;HEIGHT:2900px" coordsize="21600,21600" fillcolor="white" strokecolor="black">
    <v:shadow on="t" type="single" color="silver" offset="4pt,3pt"></v:shadow>
  </v:rect>
  <v:shape style="position:absolute;left:50;top:2650;WIDTH:1000px;HEIGHT:200px;z-index:8" coordsize="21600,21600" fillcolor="white">
    <v:textbox id="text1" inset="3pt,0pt,3pt,0pt" align="center" style="font-size:10pt;v-text-anchor:bottom-center-baseline">0</v:textbox>
  </v:shape>
</v:group>