AA with dynamic array value

[Craig Dillabaugh via Digitalmars-d-learn]

How can I create (and update) and associative array where the key 
is a string, and the value is a dynamic array of integers?

For example:

void insertValue( int[][string]aa, string key, int value )
{
     int[]* keyvalue;

     keyvalue = ( key in aa );
     if ( keyvalue !is null )
     {
         *(keyvalue) ~ value;   // This line fails.
     }
     else {
         int[] tmp;
         tmp ~= value;
         aa[key] = tmp;
     }
}


int main( string[] args) {

     int[][string] myAA;

     insertValue( myAA, "hello", 1 );
     insertValue( myAA, "goodbye", 2 );
     insertValue( myAA, "hello", 3 );

     return 0;
}

Fails with:
...(16): Error: ~ has no effect in expression (*keyvalue ~ value)

Thanks for any help.