`no identity found` when trying to "rake device"

If rake device is aborted with the following error,

$ rake device
** Invoke device (first_time)
** Invoke archive:development (first_time)
** Execute archive:development
** Execute build:device
  WARNING! Found 3 iPhone Developer certificates in the keychain. Set the `codesign_certificate' project setting.   Will use the first certificate: `"iPhone Developer: \346\225\246 \345\206\205 (A123B4CDE5)"'
CODESIGN_ALLOCATE="/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/codesign_allocate" /usr/bin/codesign -f -s "iPhone Developer: \346\225\246 \345\206\205 (A123B4CDE5)" --resource-rules="./build/iPhoneOS-5.0-Development/Hello.app/ResourceRules.plist" --entitlements ./build/iPhoneOS-5.0-  Development/Entitlements.plist "./build/iPhoneOS-5.0-Development/Hello.app"
iPhone Developer: \346\225\246\345\215\232 \345\206\205\345\261\261 (K828P5UTB8): no identity found
rake aborted!

Dropping app.codesign_certificate in your Rakefile may fix it.

# -*- coding: utf-8 -*-
$:.unshift("/Library/RubyMotion/lib")
require 'motion/project'

Motion::Project::App.setup do |app|
  # Use `rake config' to see complete project settings.
  app.name = 'Hello'
  app.codesign_certificate = "iPhone Developer: \346\225\246 \345\206\205 (A123B4CDE5)"
end