Hi Armin,
Use dummy0 for the static ip's, e.g.:
auto eth1
iface eth1 inet dhcp
auto dummy0
iface dummy0 inet static
address 172.16.2.201
netmask 255.255.255.0
broadcast 172.16.2.255
auto dummy0:1
iface dummy0:1 inet static
address 172.16.2.202
netmask 255.255.255.0
broadcast 172.16.2.255
--Mike Bird