passing information between web site and User control

[yeap7]

Hi
I have a web site which hosts an activeX (using object tag) .
This activeX is actually a user control in a class libraray project .
I wrote some code to be executed once the client press the OK buttom of the user control .
I need at a certain stage to send a array of bytes from the user control
back to the server for certain calculations and to return a new array of bytes back to the user control .
How do I do that....?

(Im a beginner of ASP.NET...)

Any help will be highly appreciated !