T46G - How to setup Voicemail

HI,
I have a T46G, using a Fritzbox DSL Router w/ DECT functionality (I am in Germany). Currently voicemail is with the Fritzbox and the Yealink displays via pop-up if there are new messages on the DECT Router. But I would like to have the voice mails / reply messages on the Yealink incl. red flash light - but how? Do I need a PBX server or so?

I did not find anything in the IFU - thx in advance for your help. oestersund