TypeData/HashTable.ps1xml

<?xml version="1.0" encoding="utf-8" ?>
<Types>
  <Type>
    <Name>System.Collections.Hashtable</Name>
    <Members>
      <ScriptMethod>
        <Name>AppendValue</Name>
        <Script>
            param(
                [parameter(Mandatory=$true,Position=0)]
                [string]$key,
                [parameter(Mandatory=$true,Position=1)]
                [object]$data
            )
            if ($this.ContainsKey($key)) {
                $newData=@($this[$key])
                $newData += $data
                $this.Remove($key)
                $this.Add($key,$newData)
            } else {
                $this.Add($key,$data)
            }
        </Script>
      </ScriptMethod>
      <ScriptMethod>
        <Name>Replace</Name>
        <Script>
            param(
                [parameter(Mandatory=$true,Position=0)]
                [string]$key,
                [parameter(Mandatory=$true,Position=1)]
                [object]$data
            )
            if ($this.ContainsKey($key)) {
                $this.Remove($key)
            }
            $this.Add($key,$data)
        </Script>
      </ScriptMethod>
    </Members>
  </Type>
</Types>