Acer Liquid Z220 Duo User Manual page 61

Selecting which SIM to use when sending a text message
If you have set SMS Messages to Always ask, you will be asked
which SIM to use each time you send a text message. Enter the
message and recipient information, then tap the Send button. A dialog
opens; tap the SIM to use and the message will be sent.
Identifying calls
Whenever you receive a call, the caller's number will be shown. You
will also be shown the name of the SIM receiving the call.
In the call log, the name of the SIM will be shown beneath the number
of the call -- whether the call was missed, answered or was an
outgoing call.
Managing your SIM cards - 61