Function in OLEDBSource components expands string to 8000

Hi, 

The sourcecolumn is 255 characters long and the destinationcolum is too. But when i'm using a function (REPLACE) in the OLEDBSource, the string is expanded to 8000 characters. Should I use a Cast to limit the string 255 again?

Error:

Truncation may occur due to retrieving data from database column "xxxxxx" with a length of 8000 to data flow column "xxxxxx" with a length of 255.   

Seems strange to me or should I do something else?

Hennie