British mobile phone maker Sendo rattled executive cages over at Microsoft (Quote, Company Info) Thursday.

The long-time supporter of the Windows for Smartphone 2002 platform for handsets said it has instead decided to license Nokia's (Quote, Company Info) Series 60 Platform for its smart phone category.

Not only that, but Sendo said it was halting all development of Smartphone-releated products. Sendo was working with Microsoft on its Z100 MS "Stinger" handset and was poised to launch the device this month in Spain and Italy.

"The Z100 will not now be coming to market," said Sendo product strategy and planning executive Ron Schaeffer.

Sendo said its decision was based on its frustration over Microsoft's reluctance to release key source code for the device, despite a $12 million investment from the Redmond, Wash.-based company.

"Earlier this fall we reviewed our smart phone strategy. While our mission of providing customers with feature-rich and ubiquitous devices remains unaltered, seeing that the Series 60 fully embraces both our mission and the new strategy we decided to approach Nokia," Sendo CEO Hugh Brogan said in a statement. "The platform utilizes open standards and technologies, such as MMS and Java, jointly developed by the industry. The platform is robust, yet uniquely flexible, bringing great benefits to licensees, operators, developers and consumers."