[Seaside] new canvas replacement for #anchorWIthDocument: searched

[Martin Schubert]

hello out there,
i can`t figure it out how the new canvas api replaces anchorWithDocument.
i want to write a document that first uploads a file and display an 
anchor to it after uploaded.

html form
        multipart;
        with: [
            html bold: 'Load version from file: '.
            html break.
            html fileUpload callback: [:f | file _ f].
            html space.
            html submitButton callback: [self save]; text: 'Load'.
    ].

    file ifNotNil: [
        html anchor;
        url: ??file urlFromFile??].

could anyone point me in the right direction? thanks a lot!