look i don't know that answer to this question i have never worked with this before. Logially if you are saying in your ASP codepage = 1255 and the client is codepage = 1340 or whatever then the page is not going to be displayed correctly.
I would think you need to determine what codepage the client is using and then dynamically generate the correct codepage on your ASP page.
I don't know how to determine the clients codepage so i can't help you with that. But once you find out how to do that then all you have to do is an elseif or case statement and generate the correct codepage.
'client codepage = variable1
if clientcodepage = 1 then
codepage = 1
elseif clientcodepage = 2 then
codepage = 2
elseif clientcodepage = 1255 then
codepage = 1255