FatalError on attempt to create folder with ShellExec Custom Action

[CadMan77]

I'm playing around with concept of Custom Actions.
I've created two CAs:
<CustomAction Id="SetCmdLine_TempDirCreate" Property="WixShellExecTarget" Value="mkdir C:\temp\a1" />
<CustomAction Id="CreateTempDir" BinaryKey="WixCA" DllEntry="WixShellExec" Impersonate="yes" />

I then call them consequently by custom PushButton:
<Publish Event="DoAction" Value="SetCmdLine_TempDirCreate">1</Publish>
<Publish Event="DoAction" Value="CreateTempDir">1</Publish>

After pressing the button I get "...Setup Wizard ended prematurely" message.
Installer log file contains FatalError on CreateTempDir.

What I'm missing?

PS:
I do know that I can create folder by means of Directory Id.

[robmen]

My guess is that mkdir isn't an executable but a command built into cmd.exe. Thus you can't shell execute it, but would need to shell execute cmd.exe to then run the mkdir command.

This is all a horrible idea by the way. Don't do this.