base64 encoding and signing (hashing)

hi list,

i have the following senario. send a message with attaching a file which needs to be base64 encoded and signing.

when i encode the file by hand and add it to the message the message is send fine.
when i add the message with cid:fileId it will be base64encoded (the same when done by hand) but i will get a message 'Hash values do not match'.
when i copy the encoded file from the raw output and add it again instead of the cid:fileId it will work again.

my gues is that the signing of the message is somehow at the wrong time done. so the hash is calculated before the file is added.

i will attach my project (it is all test data and test certificates)