Sorry, my fault, the app's name is Ultimate Roration Control (here
It's possible to try it out for 7 days for free trial to see it it works for your phone.
The app only helps you to make the correct mirroring from the phone (landscape, portraite), not making you get the HDMI work if you haven't made a proper build.prop with ROM Toolbox on the phone first.
It's all over internet to read about how that is done. Search on buld.prop + HDMI and you'll find a lot to read about it and how it's done. I'm a complete (oh well....) female noob and manage to fix it!
Also I did notice that using the HDMI cable I bought separately did not work as it was too big to fit on my LG P990. It wasn't being connected properly into the contact on the phone, the plastic is in the way to go all the way in!
By a coincidence I then found the original LG HDMI-cable in a drawer and it's a significant difference between the two in size.
Hope this info helps you guys!