If it were my car, I'd go to a Mercedes dealer and ask them for the Mobil 1 ESP 5w40 Formula M. It EXCEEDS all the requirements of the Emissions system on your TDI and is required for use in the "Clean Diesels" for Mercedes. The difference is that it has a better viscosity range for lower wear.
If you overlay the two specifications, the Mercedes 5w40 has a higher wear protection rating than the VW 5w30. Aside from that, absolutely identical except for the label that does not have the VW507.00 on it. The spec I prefer, MB229.51 and 5w40.
In a pinch, you could use the Delvac 1 5w40 ESP, this still complies for all DPF engines with aftertreatment (LowSAPS). This does have a very slightly higher Sulfated Ash content, so like I said in a pinch, but no worries of it contaminating any of the emissions system devices. It is also a Clean Diesel rated oil.