I need to replace ',' with '|' in some specific position in each row in fixed width file using SSIS VB script task.

I have a fixed width file, where I need to replace ',' with '|' in some specific position (Pos column 100 to column 200) in each row except Header and Tailor rows in fixed width file using SSIS VB script task.
I dont want to use derived column but only VB script task. Could anyone please share the script?

Thanks in advance.