[Plugin: Multisite Global Search] Permalink

Apologies if this is something very obvious, but how does one add the trailing slash and period to the permalink of the results page to ‘http//yoursite/globalsearch/.’ ?

I can change it in the edit screen to http//yoursite/globalsearch but the last slash and period get automatically removed when I hit update.

http://ww.wp.xz.cn/extend/plugins/multisite-global-search/