Custom Loxone control app

We design, sell and install home automation products from a company called Loxone which are used to, amongst other things, switch relays and lighting circuits through an app.

They have a free app available for IOS and android and a browser based interface. I am told that the app is open API.

We are looking to build a custom app, with a few commands built in. There is some information on what is involved here http://www.loxone.com/enuk/service/documentation/api/communication-logic.html

If you think then you are able to help with this then I welcome your initial thoughts and an idea of an hourly rate / potential overall cost.

I am on oh Severn ate won ate, too won for Severn ate 5 if you want to call. My company is called XO Home.