VOIP + SMS in Australia

Sorry if this isn't really on topic but I'm sick of going around in circles and signing up for things that can't do what they say on the tin.

I have a small business, and I'd like my staff and I to be able to send and receive SMS to & from clients using a web-ui or maybe even android app.

To be clear, this isn't any sort of marketing or whatever. We SMS clients to ask questions about jobs we're doing for them.

It looks like 3CX is the best PABX platform perhaps? Then I need a SIP Trunk with SMS support - and most SIP providers say they provide SMS, but the SMS functionality doesn't seem to integrate with 3CX.

It looks like 3CX definitely has SMS support, and I can see screen caps of configuration for SMS support in 3CX, but in the hosted instance provided by 3cx.com those options are not present.

So I think my question is... can 3cx support SMS in Australia? If so what is the best SIP Trunk to use for that purpose? If not, is there any other platform that will allow that?