I had a similar problem with the default email for my camera & calendar. When actually composing the email, where it says "Send using:" it says "default", you can click the track wheel and change it to whatever email you want to use.
Also Try the following:
menu>options>advanced options>default services> press the track ball & choose the default email you want>menu>save.
I posted this problem recently and this is what another member suggested.
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