Can we use macros in velocity email templates?

We're looking to track the user clicks on an email sent and we're doing that by passing a query string param. The problem is I cannot just append to the URL's in the email template.

/foo/bar#M436?referer=1 is invalid URL 

whereas I need to do : /foo/bar?referer=1#M436.

To achieve this, I need to parse url with something like...

#macro( parse_url $url)

  #set ($hash_index = $url.indexOf('#'))
  #if( $hash_index > -1 )
   #set ($first_part = $url.substring(0, $hash_index))
   #set ($second_part = $url.substring($hash_index))
   #set ($new_url = "${first_part}?referer=1${second_part}")
  #else
   #set ($new_url = "${url}?referer=1")
  #end

#end

#parse_url( ${notification.message.webUi.url} )

I have had no luck to get this to work : http://velocity.apache.org/engine/1.7/user-guide.html#velocimacros

It does work, however, if I get rid of the macro. Any input is appreciated. 

Also - does Lithium provide any tracking through a dashboard on number of click activity via email?