At a site IP phones of AVAYA are going to be rolled out soon.

I shall define custom DHCP options, but can't find documentation
covering this task. I also cannot find in iManager or DNSDHCP4.EXE
management console the magic button to add custom options.

What do I miss?

A picture of the summary of the example setting should be attached here.

It's about all the options, that have noted "TENOVIS" in the row
"Hersteller" (that's "vendor")

Any suggestions appreciated, or just an URL to the docs covering that.

Thanks, Rudi.