when you are not logged into my website and you click post

when you are not logged into my website and you click post new classified advert it takes you to this page

http://ilovestaffordshire.co.uk/classifieds/signin/?redirect_to=http%3A%2F%2Filovestaffordshire.co.uk%2Fclassifieds%2Fadd-classified%2F

where you can register or login..
however if you login you are then redirected to this page

http://ilovestaffordshire.co.uk/login/

as i have a custom login screen activated...

is there a way to go to this custom login screen by default and bypass the classified login screen?? or is it essential they login via the classified screen?