Can I publish keyframed parameters in an FCP generator?

Question

Hi
I'm making an FCP generator in Motion and have a layer which moves from (0,0) to (x,y) and then goes back to (0,0).
What I would like to do is publish the (x,y) position so that I can change this in FCP. I have currently keyframed the animation with a dummy value for (x,y), but when I try to publish this it works fine in the Project Publishing pane (with values and keyframes) but when I bring it into my FCP timeline I have no keyframes and a zero value.
I can go in and manually add keyframes to my position parameter, but that rather spoils the whole benefit of doing it as a template. If the keyframes carried over it would be a start. If I could isolate the (x,y) keyframe and just allow that to be changed while maintaining the (0,0) that would be awesome.
If you cannot do this is it a bug which may at some point be fixed, or is it not meant to do this? The fact that the keyframes are there in the Project Publishing pane makes me think that they should export to FCP.
Would this work if I set up a rig? Can I specify values at certain points in time and then use a slider or similar to specify where the position value will go at my mid-keyframe? I haven't used rigs before but am happy to learn how to use them if they can do what I want.
My other thought (although I think this will become an inelegant solution) was that I could use a ramp to behaviour on x-position and one on y-position, and publish these values with ramps back to (0,0). At this point that doesn't seem too complicated, but I actually have a number of layers doing a number of things [and sometimes starting at (x,y) and moving to (0,0) and then back to (x,y)] so would have quite a lot of ramp values published which would become confusing, if this would work at all.
Perhaps I would have to use a rig to combine some of these if this is my only option?
Sorry if I'm at all vague. I know very clearly what I want to do and sometimes get befuddled explaining, but if I can publish keyframed position parameters (or preferably just the mid-point) I know that would solve it quite easily.
I'll keep experimenting and update with how I get on, but any help would be greatly appreciated.
Cheers

Answer 1

Sorry, my mistake. I forgot to mention that this is an image movement for a slideshow and will be repeated (with the variable (x,y) values) multiple times in the timeline.
Yes, if it was a single instance then keyframing in FCP would be fine. For the thirty or so occasions I will need to keyframe it makes more sense to automate if possible.
I tried rigs but the same thing happens.
Then I managed to make something work whereby I keyframed the rig to go from 0 to 100 to 0 and set the corresponding x positions as 0 and 100. Publishing this makes the layer move to (0,100) and back to (0,0) when the slider is set at 100 and lowering the slider lowers the x position reached.
This only works in one direction (can't move left and right) so isn't ideal.
Then I changed the keyframed animation to two ramps on the x position and it's actually more elegant than I thought. One ramp goes from 0 to x and stops with an end offset. Then the second ramp kicks straight in taking it from 0 to -x. Set up a rig with a slider connected to both ramps end values, one directly connected and one inversely connected. Hey presto, one slider connecting to a variable move in the x direction that also accepts negative values (I played with the max and min values of the slider).
I just need to do the same for y position. This should also work where I start at (x,y) as I will just connect to the start value and tweak the start offset to time my move.
Hope that makes sense. If anybody wants to do something similar and needs further explanation please ask. This is truly amazing. I can set up a zoom in to start and end anywhere on screen (i.e. zoom top left corner into middle of screen) and control where we zoom from within FCP... or control other parameters in a similar way.