c# - Wix File Association - Misunderstanding -

i have application, , want use own file extension opens application when double clicked. i'm using wix build installer, , understand can make use of file association in .wxs file. snippet file looks this:

<directoryref id ="installfolder">         <component id ="rbupdate.exe" guid="*">             <file id="rbupdate.exe" keypath="yes" source="$(var.rbupdate.targetdir)rbupdate.exe" />             <progid id ="myprogid" description="rbupdate data files" advertise="yes">                 <extension id ="rbu" contenttype="application/rbu">                     <verb id ="open" command="open" targetfile="rbupdate.exe" argument="&quot;%1&quot;"/>                 </extension>             </progid>         </component>     </directoryref>      <feature id ="productfeature" title="rbupdatesetup" level="1">         <componentref id ="rbupdate.exe"/>     </feature> 

this builds fine, if i'm honest, i'm new , aren't quite sure does. main question how create instance of created file type? files i'm creating not going result of running application, , manually made externally application, load. want able make xml file, name .rbu extension, , have open application

thanks

i not renaming xml files .rbu! working example of how use file association wix anyway, not waste time :l