The online World Politics Review ran an article dated 28 November 2011 by Brian Dabbs titled "Israel Targets East Africa with Kenya Security Pact."
Although the first two paragraphs appear here, the entire article in only available by subscription.
I am quoted in the article as pointing out that this new development will serve as a potential recruitment tool for al-Shabaab only if it involves Israeli support for Kenya's intervention in Somalia.
This does not appear to be the intent of the security arrangement; it seems to focus on helping to improve internal Kenyan security. If this is, in fact, the case, it will be very difficult for al-Shabaab to use the pact for propaganda purposes.
Here's my quote from the article: “If [homeland security] is the focus, I don’t see it as an advantage to al-Shabaab,” said David Shinn, former U.S. ambassador to Ethiopia and Burkina Faso. “It will only be a recruitment tool if it involves Israelis in Somalia.”