Hi Brad , Thank you for your reply .
I am already using SMTP solution (Sample app was done by Roland Smith ) , and it works quite well .
But I have some cases that users requires to see , edit emails content before sending it .
I thought about designing my own email screen , but it's hard to implement all features as emails applications have ( text formatting , tagging emails , reminders ....etc ) .
So opening default email application is a suitable solution for me here ,except it doesn't support attachments ,
hope there is a way to do it .