How can I instantiate a contract from a factory and, in the same call, send msg.value to it?

Question

WHAT I WANT TO DO: call another contract's constructor function, instantiate that contract, and subsequently send Ether to it in the same function.
WHAT HAPPENS: an instance of the other contract gets created, and Ether is transferred, but none of the functions on the newly created contract work. I get call to SmartGift.{function name} errored: Cannot read property 'length' of undefined when I try to do anything on the new contract.
PROBLEM FUNCTION:

function createSmartGift(address _recipient, uint32 _expiry, string _donorMsg) public payable returns(address){
        address newGift;
        newGift = new SmartGift(_recipient, msg.sender, _expiry, _donorMsg);
        giftExists[newGift] = true;  

        uint id = gifts.push(Gift(newGift, _donorMsg,false, _expiry));
        giftToOwner[id-1] = _recipient;
        recipientGiftCount[_recipient]++;
        donorGiftCount[msg.sender]++;

        newGift.transfer(address(this).balance); // I WANT TO THIS, BUT GET ERROR

        return newGift;
    }

OTHER NOTES: I've tried both address(this).balance and msg.value. And the target contract has a payable fallback function.
Also, everything works fine if I separate out the newGift.transfer() into a separate function that I have to call separately. That's my backup plan, but I want the customer to only click once, not twice!

Answer 1

I'm not sure why that isn't working, but as a workaround, you can just make SmartGift's constructor payable and do this:

address newGift = (new SmartGift).value(address(this).balance)(_recipient,
    msg.sender, _expiry, _donorMsg);