strServerName ="localhost"
strRootPath="g:/documents" ''虚拟目录路径
strVRName="Test" ''虚拟目录名称
strDefaultDoc="index.asp" ''起始文档

Dim objIIS
''MsgBox "IIS://" &  strServerName &  "/W3SVC/1"

On Error Resume Next
Set objIIS=GetObject("IIS://" &  strServerName &  "/W3SVC/1")

If err=-2147024893 Then
MsgBox "IIS不存在!" &  vbcrlf &  "请验证IIS是否已正确安装!",vbcritical
Wscript.Quit
ElseIf err<>0 Then
MsgBox "未知错误!",vbcritical
Wscript.Quit
End If

On Error GoTo 0

Set objVirtualDir=objIIS.GetObject("IISWebVirtualDir","Root")
For each VR in objVirtualDir
If VR.Name=strVRName Then
MsgBox "虚拟目录" &  strVRName &  "已存在!",vbinformation
Wscript.Quit
End If
Next

On Error Resume Next
Set fs=Wscript.CreateObject("Scripting.FileSystemObject")
Set objFolder=fs.GetFolder(strRootPath)

If err=76 Then
MsgBox "路径" &  strRootPath &  "不存在!",vbcritical
Wscript.Quit
End If

Set objFolder=nothing
Set fs=nothing
On Error GoTo 0

On Error Resume Next
Set VirDir=objVirtualDir.Create("IISWebVirtualDir",strVRName)
VirDir.AccessRead=true
VirDir.Path=strRootPath
VirDir.DefaultDoc=VirDir.DefaultDoc &  "," &  strDefaultDoc

VirDir.setInfo

If err<>0 Then
MsgBox "创建虚拟目录失败!",vbcritical
Else
MsgBox "虚拟目录" &  strVRName &  "成功创建在服务器" &  strServerName &  "上!",vbinformation
End If

代码的关键在于创建虚拟目录，及其中的配置：

Set VirDir=objVirtualDir.Create("IISWebVirtualDir",strVRName)
VirDir.AccessRead=true
VirDir.Path=strRootPath
VirDir.DefaultDoc=VirDir.DefaultDoc &  "," &  strDefaultDoc

VirDir.setInfo