Try this. Put mod_cblogin in an unused position in your template. Then make an article with this in the content: {mosloadposition cbloginposition}, where cbloginposition is the name of the position where u placed mod_cblogin. Make a menu item pointing to the article. mosloadposition allows you to put a module in content. Hope this works.
Take a look at this great tutorial for Joomla 1.5 of how to load a module into content with a menu link. Solved the the same issue for me very cleanly by comparison to some of the other workarounds.