F5 BIG-IP WebGUI intermediate certificate

I just tried that, unfortunate it still doesn't work. Here's the PKCS12 file containing both certificates:

$ echo ''| openssl pkcs12 -in dbn-vp6.p12 | grep BEGIN
Enter Import Password:
MAC verified OK
-----BEGIN CERTIFICATE-----
-----BEGIN CERTIFICATE-----
Enter PEM pass phrase:

The device accepts the PKCS12 file no problem, the Device Certificate/General Propertis shows two entries now, one for the device certificate, the other one for the signing one. But if I connect to the management interface I still get only the device certificate as part of the TLS handshake:

$ echo '' | openssl s_client -connect dbnintaccvp06:443 -showcerts  | grep BEGIN
-----BEGIN CERTIFICATE-----

For comparison this is what should happen if the correct certificate chain is presented:

$ echo '' | openssl s_client -connect www.google.com:443 -showcerts  | grep BEGIN
-----BEGIN CERTIFICATE-----
-----BEGIN CERTIFICATE-----