I've been searching for the same thing. I noticed the only way it comes up is if you manually check for VM. Haven't found anything worth wild on the youmail side of things. Gonna start searching the forums soon.
I haven't found anything so I'm going back to Verizon's voice mail. It's crazy that you wont be notified immediately when you have a voice mail, it defeats the purpose.
IIRC, it should be possible to have an email and/or text message sent to your phone alerting you to a new voice mail. What you won't get is the voicemail status indicator like you would with Verizon's service.
Don't you guys see the "missed call" icon show up? True, that not every missed call results in a voice mail. If I see a missed call I just wait and usually get a text within a minute or so. If I see a missed call and no "new voicemail" text within a minute, then I asume no message was left.
Keep in mind that you can set your youmail preferences on the home page of youmail from a PC. You MAY have the option of text or email turned off.