Sounds nice ... but doesn't work for me. What I typed:

dbus-send --type=method_call --dest=com.nokia.osso_pdfviewer /usr/bin/osso_pdfviewer com.nokia.osso_pdfviewer.mime_open string:file:///home/user/MyDocs/.documents/osso_software_copyright.pdf

The pdfviewer opens, but without document.
Where is the problem?

Just a hint: a real example without placeholders <>... is usually better