Over a year ago Hariri's Future Movement started setting up Sunni Islamist terrorist cells (the PSP and LF already had their own militia since the civil war and despite the Taif Accords requiring militia to disarm they are now rearmed and itching for action and trying hard to provoke Hezbollah).
The FM created Sunni Islamist 'terrorist' cells were to serve as a cover for (anti-Hezbollah) Welch Club projects. The plan was that actions of these cells, of which Fatah el-Islam is one, could be blamed on al Qaeda or Syria or anyone but the Club.
To staff the new militias, FM rounded up remnants of previous extremists in the Palestinian Refugee camps that had been subdued, marginalized and diminished during the Syrian occupation of Lebanon. Each fighter got $700 per month, not bad in today's Lebanon.