applying for the second time for student Visa , need some tips

Hi,

I have been admitted to MBA program in UQAM (Universite de Quebec a Montrea) for winter semester 2009.
I also was founded 12,000$ per year for research assistantship. The canadian Embassy refused my Visa becoz :
1.They were not sure I will be coming back to my hometown Tehran/Iran after my education.
2. The thought Im not a genuine student.
I was really shocked since I honetsly have no idea how Im supposed to make them sure of these two reasons.
Yet , I contacted the embassy and they told me that I can apply again,for the next semester perhaps, incase my situation varies considerable. Now I have this question, management schools in Montreal have an agreement that their students can take courses in any other management school in Montreal and since UQAM is a french speaking school , the offered me to take classes in Concordia university which is an English speaking school.The thing is that UQAM does not offer summer semester but concordia does. Now , since my professor needs me in his research team he has agreed to give me a letter indicating that 1.he needs me to go there in spring , ASAP and since they dont have summer semester , I can start educating in Concordia, and their classes start in May.
I wanna know if this letter is fair enough for these tough officers and if anyone has ever been in the same situation , or if anyone has been able to get the Student Visa after being refused once.
Any tips?
Reall appriciate it.