poor remote range

[PeterH]

I've got a ML700 opener and a metal door. The remote works fine inside the garage but won't open the door from outside more than about 3 feet from the door. Chamberlain's helpline suggests using a ANT4X-1LM external antenna but it requires a co-ax connection while the ML700 has a single wire aerial soldered straight onto the circuit board.

Anyone know how to connect this aerial so it will work? Thanks