Using entrance effects in advanced actions

Howdy!

I've had a good trawl through the forums, and haven't had much luck.  Plenty of posts for people looking to use motion paths within advanced actions (took me a while to figure out they were relative and not absolute!) and I'm comfortable in building custom effects and using these in advanced actions.

The thing I'm trying to do (and it seems absurd that I can't find anyone else with this problem!) is this:

How do you use entrance effects in advanced actions?

I have two buttons, each with some text and an image that is revealed when the button is clicked.  So far so good.

In addition, when you click button 1 the content that is revealed on button 2 disappears and visa versa.  Still all good.

I'm trying to include an entrance effect on the content when the buttons are clicked and it all falls apart... The show command shows the image, THEN applies the entrance effect, swapping the show and apply effect command around means that the show command doesn't start until the effect is complete but at this point the content is still 'hidden' so you can't see the effect.

For information sake I'm fully prepared for the answer of "you're fundamentally building your advanced action in an inefficient way", I've gone for a very simple:

Button 1:

Execute advanced action when:

1 = 1  (I've got into the habit of not using standard actions for anything, makes it easier if I need to make it conditional later on - some thoughts on this would be great!)

Show: Content for Button 1

Hide: Content for Button 2

Button 2:

Execute advanced action when:

1 =1

Show Content for Button 2

Hide Content for Button 1

I suspect there is a more efficient method that will allow me to achieve what I want to - so I'm prepared for that answer!

Any help would be wildly appreciated!

Thanks

Ewan