Some characters replaced by '?'

[abhishek jain]

Dear friends,
I use XML Post to send SMS Via kannel.
If i send some of the following characters !"£$%^&*()_+{}@:>?<` `¬`

the SMS i received has ??? for some of the above characters,

Any ideas why?

-- 
Thanks and kind Regards,
Abhishek jain