Question on DSC xWebAdministration


can somebody please explain me how to set the following setting in IIS with DSC xWebAdministration Module?

xWebConfigProperty set-maxRequestLength {
   WebsitePath    = 'IIS:\Sites\Default Web Site\Microsoft-Server-ActiveSync'
   Filter         = 'system.web/httpRuntime'
   PropertyName   = 'maxRequestLength'
   Value          =  '40858'
   Ensure         = 'Present'

You have the configuration written , can you make us clear on what is the problem you are facing here ?