Found this in a comments thread over at Shacknews...

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How to get command line launching from ASE to work:

Go into your ASE folder and open filters.txt. Search for "Battlefield 2". Change the JoinTemplate line to:

JoinTemplate: {EXEPATH} +restart 1 +joinServer {ip} +port {port} [ +password "{PASSWORD}"]

Then delete the whole JoinMsg line. There should be an update either today or tomorrow (most likely tomorrow), but until then, you can launch into games using this method.
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One thing to note is farther down in the thread someone said the +password portion wasn't working so it may not work to get into the Private server but supposedly for public servers it should work. I would imagine you still have to log-in to EA but who knows.