Manipulate data from Proxy before store

[xxhalfpint]

I have an older service that I can't change.
It's passing me some data not in array.

So what I need to do is take the data I'm getting and change it to an array before adding it to the store.
Example:

I'm getting from the service in json:
{ "id": "1234",
"isAdmin": true
}

I need to change it to this before it gets stored:
[{ "id": "1234",
"isAdmin": true
}]

So where would I go about this?
Right now my proxy looks like this.
proxy: {
type:'ajax',
url: '/service/etc.',
reader:'json'
}
I was thinking Ext.data.proxy.Memory, some guidance with doing this would be great!
Thanks for the help in advance!!

[scottmartin]

You can use listeners to determine when to change your data.

listeners: {
    beforeLoad: function(store, operation){ // 1st; no data items
        console.log('beforeLoad');
        console.log(store.data.items);
    },
    dataChanged: function(store){ // 2nd; data items populated, controls still empty

        console.log('dataChanged');
        console.log(store.data.items);
    },
    load: function(store, records, success){ // 3rd; data items populate, controls show data
        console.log('load');
        console.log(store.data.items);
    }
}
});

Regards,
Scott.