Add 2 checkbox when install with Wix is over

I have an setup for my C# application. At the end of setup I added a checkbox proposing to launch application. It works good. But i'm unable to add a second checkbox proposing to launch an optional installer.

There is my code:

<?xml version="1.0" encoding="UTF-8"?>
<?define compagny = "myCompagny"?>
<?define product = "myProduct"?>
<?define version = "!(bind.FileVersion.MyProject.exe)"?>
<Wix xmlns="http://ift.tt/1cKQ1oM"
     xmlns:util="http://ift.tt/18LfQpH">
  <Product Id="*"
           Name="$(var.product)"
           Language="1033"
           Version="$(var.version)"
           Manufacturer="$(var.compagny)"
           UpgradeCode="PUT-GUID-HERE">
    <Package InstallerVersion="200" Compressed="yes" InstallScope="perMachine"/>
    <Icon Id="icone.ico" SourceFile="$(var.MyProject.ProjectDir)\Images\icone-VR.ico"/>
    <Property Id="ARPPRODUCTICON" Value="icon.ico"/>
    <MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName] is already installed."/>
    <Media Id="1" Cabinet="MyProject.cab" EmbedCab="yes"/>

    <Feature Id="ProductFeature" Title="$(var.product)" Level="1">
      <ComponentGroupRef Id="ProductComponents"/>
      <ComponentRef Id ="ApplicationShortcut"/>
      <ComponentRef Id ="ApplicationShortcutDesk"/>
    </Feature>

    <WixVariable Id="WixUILicenseRtf"
                 Value="..\license.rtf"/>
    <WixVariable Id="WixUIBannerBmp"
                 Value=".\Resources\WixUIBannerBmp.bmp"/>
    <WixVariable Id="WixUIDialogBmp"
                 Value=".\Resources\WixUIDialogBmp.bmp"/>

    <Property Id="WIXUI_EXITDIALOGOPTIONALCHECKBOXTEXT" Value="Launch $(var.product)" />
    <Property Id="WIXUI_EXITDIALOGOPTIONALTEXT" Value="Warning. If you don't have optionnal package, consider to install it."/>

    <Property Id="WixShellExecTarget" Value="[#MyProject.exe]" />
    <CustomAction Id="LaunchApplication" BinaryKey="WixCA" DllEntry="WixShellExec" Impersonate="yes" />

    <UI>
      <UIRef Id="WixUI_Minimal"/>
      <Publish Dialog="ExitDialog"
               Control="Finish" 
               Event="DoAction" 
               Value="LaunchApplication">WIXUI_EXITDIALOGOPTIONALCHECKBOX = 1 and NOT Installed</Publish>
    </UI>
  </Product>

  [...]
 </Wix>

How can I add another CheckBox to launch ./Resources.myOptionalPackage.exe ?