Domain Mapping simply does not work

I have installed & network activated the Domain Mapping plugin on pinsoftstudios.co.za which is a multi-site.

I have created the following sub-sites:

http://pinsoftstudios.co.za/dous/
http://pinsoftstudios.co.za/aboutsales/

I have changed the DNS A RECORDS to the IP for pinsoftstudios.co.za for the following 2 domains:

http://howdo.us
http://allaboutsales.co.za

I have done the necessary mapping within http://pinsoftstudios.co.za/dous/ & http://pinsoftstudios.co.za/aboutsales/

I need to have the sites resolve as follows:

http://howdo.us to http://pinsoftstudios.co.za/dous/
and
http://allaboutsales.co.za to http://pinsoftstudios.co.za/aboutsales/

I simply cannot get this to work since howdo.us just gives me a blank page & allaboutsales.co.za still goes to it's original location.

I have spent many man hours on this - Pls, pls I need some asistance on this urgently!