BuddyPress.org

Hi
How can I make topic permalinks to be the latest post, in activity page?
I mean : when I click on a topic link in activity page, I go to the last page of that topic, or the last post.
I made this with “php echo bp_forum_extras_topic_last_post_link( 15 );” in the group forum pages, but I don’t know how to do it in the activity page

(my main problem is that some permalinks in activity page directs to no where!!, some times the topic name in the url brokes and an %d appears to the end of the url, or some times the group slug or topic slug changes to strange characters. as a resault when clicking on such permalinks you could not reach that topic! (my website language is Persian (an utf-8 encoding)) so because I cannot solve this odd problem, I decided to it in another way)

example:

AA posted on the forum topic BB in the group CC
AA= username
BB= the latest post link of this topic
CC= the group link.