[Pharo-dev] using Form

Hi all, i have been trying to work with the Form class (Graphics-Display Objects), to get a base 64 "form" (a String) representing the given Form. I already now i can do the oposite, like this: Form fromBinaryStream: (Base64MimeConverter mimeDecodeToBytes: aString readStream). But i cannot find the right way to do it. Right now i am doing this: (Base64MimeConverter mimeEncode: (aForm bits readStream)). Which, surprisingly, gives me a different form. Any ideas what i am doing wrong here? -- lets reign all together