WiX installer xml add folder

Question

I read all topic for this question on stackoverflow but i don't find the answer because i don't use Visual Studio for my installer.

I have this (config.wxs):

<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
    <Product Id="*" UpgradeCode="PUT-GUID-HERE" Version="1.0.0.0" Language="1033" Name="My Application Name" Manufacturer="My Manufacturer Name">
        <Package InstallerVersion="300" Compressed="yes"/>
        <Media Id="1" Cabinet="myapplication.cab" EmbedCab="yes" />


        <Directory Id="TARGETDIR" Name="SourceDir">
            <Directory Id="ProgramFilesFolder">
                <Directory Id="APPLICATIONROOTDIRECTORY" Name="My Application Name"/>
            </Directory>
        </Directory>


        <DirectoryRef Id="APPLICATIONROOTDIRECTORY">
            <Component Id="myapplication.exe" Guid="PUT-GUID-HERE">
                <File Id="myapplication.exe" Source="MySourceFiles\MyApplication.exe" KeyPath="yes" Checksum="yes"/>
            </Component>
            <Component Id="documentation.html" Guid="PUT-GUID-HERE">
                <File Id="documentation.html" Source="MySourceFiles\documentation.html" KeyPath="yes"/>
            </Component>
        </DirectoryRef>


        <Feature Id="MainApplication" Title="Main Application" Level="1">
            <ComponentRef Id="myapplication.exe" />
            <ComponentRef Id="documentation.html" />
        </Feature>
    </Product>
</Wix>

But i wouldn't just the files MyApplication.exe and documentation.html but all the MySourceFiles\ folder. I tried some solutions without success.

How include all the file of MySourceFiles folder into my installer ? After deployment i would have into programfile\my application name\MySourceFiles\ with all the files.

EDIT: I read this topic but i don't understand how it works because by example i have :

<ItemGroup> 
... Your wxs files ...
<HarvestDirectory Include="$(variable)\MySourceFiles\">
  <ComponentGroupName>CG_YOUR_GROUP</ComponentGroupName>
  <DirectoryRefId>DIR_REFERENCE</DirectoryRefId>
  <AutogenerateGuids>false</AutogenerateGuids>
  <GenerateGuidsNow>false</GenerateGuidsNow>
  <SuppressUniqueIds>true</SuppressUniqueIds>
  <SuppressCom>true</SuppressCom>
  <SuppressRegistry>true</SuppressRegistry>
  <SuppressRootDirectory>true</SuppressRootDirectory>
  <PreprocessorVariable>var.Property_Preprocessor</PreprocessorVariable>
</HarvestDirectory>
</ItemGroup>

Can i use my variable directory into .wxs file ? Can you enlighten me ?