Inserting Custom Action between Dialogs (InstallUISequence) in WiX

I have two custom dialog boxes (plus the required ones ExitDlg, FatalErrorDlg, etc.), the first one sets a property using an Edit control and the second one shows this property using a Text control. Here is the meaningful code:

<Dialog Id="DialogA" ...>
  <Control Id="ControlEdit" Type="Edit" Property="MY_PROPERTY" .../>
  <Control Id="ControlNext" Type="PushButton" ...>
    <Publish Event="EndDialog" Value="Return" /></Control>
</Dialog>

And then the second dialog:

<Dialog Id="DialogB" ...>
  <Control Id="ControlText" Type="Text" Text="[MY_PROPERTY]" .../>
  <Control Id="ControlBack" Type="PushButton" ...>
    <Publish Event="EndDialog" Value="Return" /></Control>
  <Control Id="ControlNext" Type="PushButton" ...>
    <Publish Event="EndDialog" Value="Return" /></Control>
</Dialog>

And the action sequence:

<InstallUISequence>
   <Show Dialog="DialogA" Before="MyCustomAction" />
   <Custom Action="MyCustomAction" Before="DialogB" />
   <Show Dialog="DialogB" Before="ExecuteAction" />
</InstallUISequence>

The custom action changes the value of MY_PROPERTY. My problem is how to make the Back button in DialogBget back to DialogA. Using NewDialog is simple, but then I can't get the custom action to be executed between the dialogs, or can I?

edit - 2013-05-02

After the answer from @caveman_dick, I tried to change the DialogA almost like he said, but instead of using EndDialog, I changed to Action="NewDialog" Value="DialogB". But now the Custom Action isn't being called. If I remove t