Applescript to fix emails with hidden attachments

set newFileName to (path to temporary items folder from user domain as string) ¬
    & (random number from 10000 to 99999) ¬
    & ".eml"
tell application "Mail"
    set selectedMails to the selection
    if the length of selectedMails is greater than 0 then
        repeat with theMessage in selectedMails
            set newSource to my replaceText("Content-Type: multipart/related;", "Content-Type: multipart/mixed;", source of theMessage)
            set newFile to open for access newFileName with write permission
            write newSource to newFile starting at 0
            close access newFile
            open newFileName
        end repeat
        tell application "Finder" to delete file newFileName
    else
        display alert "Selezionare uno o più messaggi e riprovare"
    end if
end tell

on replaceText(find, replace, someText)
    set prevTIDs to text item delimiters of AppleScript
    set text item delimiters of AppleScript to find
    set someText to text items of someText
    set text item delimiters of AppleScript to replace
    set someText to "" & someText
    set text item delimiters of AppleScript to prevTIDs
    return someText
end replaceText