FIX: Fixes D99B segments according to service.unece.org/trade/untdid/d99b

[Udaberrico]

Hi!

I am just working on a parsing of an invoice for Deutsche Telekom and found two segments where D99B seems to be incomplete according to https://service.unece.org/trade/untdid/d99b/trcd/trcdc829.htm and https://service.unece.org/trade/untdid/d99b/trcd/trcdc534.htm.

I am not sure if I'm doing this right, I just started working on parsing these messages ;-)