Hi Anji,
Ideally, it does not make sense to run the BSP application page through transaction launcher, when you can easily do this by adding the application page in navigation bar profile.
Even then if you want to do it through transaction launcher, then the easy way out to know the URL is test that application and then copy the URL and give it in define URLs for transaction launcher.
Please let me know, if you still face any issues.
Regards jotsaroop singh