Well, this settles it: the title for the third Secret Missions book by Ryder Windham is The Space Siren instead of Duel at Shattered Rock as mentioned by amazon.com.

Today I received the UK Puffin book Clone Wars: Curse of the Black Hole Pirates, which will be the second Secret Missions book in the US (to be published on July 22). Curiously enough, the UK-version is not part of an overall Secret Missions series as is the US-version...

Anyway, in the back, it stated that the next book will indeed be called: The Space Siren. Here's the summary for that book, to be published on February 17, 2011:

An unexpected encounter with the bounty hunter Aurra Sing leaves the young Jedi Nuru Kungurama with a possible clue to find his missing Jedi Master, Ring-Sol Ambase. But before Nuru can investigate, Overseer Umbrag of the Techno Union seizes a Republic freighter and flees across space, leading the clone troopers of the Breakout Squad to a deadly confrontation on the sand planet, Tatooine.

Oh yeah, a little something I like to mention (because I like it very much). Ryder Windham added the following acknowledgement in the back of Curse of the Black Hole Pirates:

Big thanks to Jason Fry, coauthor with Dan Wallace of Star Wars: The Essential Atlas, who generously plotted the hyperspace routes used in this story.

Update: well, this is getting curious... In their Spring 2011 juvenile catalog (downloadable PDF), Penguin has the Amazon-title of Duel at Shattered Rock in their announcement for Secret Missions # 3... So while the back of the UK's Curse of the Black Hole Pirates mentions The Space Siren, this new catalog goes back to the old title...

Anyway, the following description is from page 226 from the Penguin catalog:

Young Jedi Nuru Kungurama and the clone troopers of Breakout Squad receive orders to escort new allies across space to Coruscant. But the diplomatic mission turns deadly when the identity of a mysterious saboteur is revealed and Nuru encounters a deadly armored warrior with ties to Count Dooku. This series is written by acclaimed writer Ryder Windham, who has authored over 50 Star Wars books.

Does that sound like the description above? Nope... Well, I guess time will tell...