Galol,
The ICU doesn't "Invade" anywhere.
They are "Invited".

Remember that.
On a serious note, it appears that the presence of Ethiopian troops is somehow drawing things to war.
Because if there were no Ethiopian troops, the ICU would have been more reckless and have already tried to capture it.
But the presence of Ethiopian troops is is causing them to be a little more careful, all the while giving the extreme elements of the ICU the ability to 'manage' the more moderate elements like Sh. Shariif.
I was talking to a buddy from the same subclan as Sh. Shariif.....this is roughly what he said:
Sh. Shariif is not cunning, nor is he a politician and he's relatively junior.......but he's the Abgaal face that North Mogadishu needed to support the ICU as well as the moderate face that can deflect attention from the extremists. There is some concern that once the political aims are achieved through Sh. Shariif, he will be further and further marginalized to the point of symolic chair.
From what I understand, there is a severe split within the ICU in terms of direction.
Kismayo was a serious turning point..........because some elements of the ICU were 'communicating' with Hiiraale trying to get him back whereas some were spearheading it, like Turki.
The next turning point was probably the tribal militias fighting under the ICU who killed the patients in the hospital.