The Joomla Setup can be performed in 3 easy step :

1. Install the Joooid plugin

Download the plugin here.

Go to your Administrator Panel, 

click on Install/Uninstall from the Extension Tab (fig. 1) :

fig.1

Click on the Browse button and choose the file you downloaded, then click on Upload File & Install.

2. Enable the plugin

Go to the plugin manager in the Extensions tab (fig. 2)

fig.2

Search the XML-RPC plugins and enable them (Joomla, Blogger API, Joooid API),

make shure that all the items are checked (fig. 3).

fig.3

Edit:

3. Enable the XML-RPC Webservices

Click on Global Configuration in the Site Tab (fig. 4),

fig.4

click on System and check "yes" on the Enable Web Services radio button (fig. 5).

fig. 5

That's all, now go out and post something!!!

p.s. there is some extra configuration to do for to obtain  Google Maps in articles and Shadowbox in the galleries.