If i understand correctly you can either use a xml content match assertion or you could use a script assertion (groovy script).
Can you confirm the date values youd expect in the result?
if this helped answer the post, could you please mark it as 'solved'? Also if you consider whether the title of your post is relevant? Perhaps if the post is solved, it might make sense to update the Subject header field of the post to something more descriptive? This will help people when searching for problems. Ta