Accessing contents of associative arrays in an optimal way

[phant0m via Digitalmars-d-learn]

Suppose I have AA of structures:

struct Foo {
     int value;
     string name;
}

Foo[int] records;

As far as I know, AA implemented as a hashtable. So, will there 
be two searches performed (one search for each line)?
records[3].value = 10;
records[3].name = "name";

How can I access elements of this AA by a "reference"? In C++ I 
can use reference to an element of the map:
Foo& foo = records.find(3).second;
foo.value = 10;
foo.name = "name";

I found that in D I can use a "with" keyword to achieve the same 
effect:
with(values[0]) {
     value = 10;
     name = "name";
}

Is this the only optimal way?