Head of corporate marketing for the region Sarah West quit RIM last week after two years with the company.
She is set to join the Brunswick agency towards the middle of next month, as a partner.
RIM has hired former Orange global brand communications director Kristof Fahy to cover West's brand-related responsibilities. Fahy joined the company last week as director of brand EMEA.
EMEA corporate PR manager Hannah Jackson said RIM had not found a permanent replacement for West. Jackson and EMEA head of PR Meigan Terry are overseeing PR duties across the region. UK PR manager Nerissa Townend assumes West's UK remit.
RIM is awaiting a crucial High Court judgement, which could stop its UK customers from using their BlackBerrys.
A Luxembourg-based intellectual property company is suing RIM, claiming it owns the patent for a piece of technology that allows data to move from a computer to a handheld device. Inpro patented the technology in April 1996.
If the court finds against RIM, it could result in the UK's 375,000 BlackBerry users losing their service. However, it is thought more likely that the judge will force RIM either to make a financial settlement or to make wholesale changes to its technology, should it lose the case.
Prior to RIM, West worked at software vendor Orchestream between 2000 and 2002 as director of the company's corporate communications.
She was previously the company's director of North American marketing.