Effects Motion XML X/Y Coordinates

I am trying to slide in text or menu objects from the right (outside the viewable area) to the left (viewable area) based on button events. I created the motion rightleft and leftright effects, modified the ending points, saved the XML, and then used the custom motion effects with Advanced Actions. Everything works, but I would like to streamline the editing and specify the starting / ending points of the effect motion by editing the XML file. I am getting real close, but not quite there. I would like the starting point to be the current location of the object and the ending point to be somewhere on or off screen. Using trial and error, I modified every X/Y value I could find, and again am close, but cannot spend more trial and error time. Can someone identify with attributes I should edit to acheive my desired effect? Also, what do the X/Y values signify (pixels, screen position)....The following is my current RightToLeft motion path XML...

<effect_sequence item_duration="10.0">

<effect name="JLRightToLeft" display_duration="2.0" appear_after="0.1" enabled="1">

<Motion xmlns="fl.motion.*" xmlns:geom="flash.geom.*" xmlns:filters="flash.filters.*" duration="60">

<source>

<Source frameRate="30" x="0" y="0" scaleX="1" scaleY="1" rotation="0" elementType="movie clip" instanceName="abc" symbolName="Symbol 1">

<dimensions>

<geom:Rectangle left="0" top="0" width="97" height="50"></geom:Rectangle>

</dimensions>

<transformationPoint><geom:Point x="0.0" y="0.0"></geom:Point>

</transformationPoint>

</Source>

</source>

<effect_config effect_type="motion_path"></effect_config><Keyframe index="0" tweenSnap="true" tweenSync="true" x="1.0000000" y="1.00000000">

<tweens><SimpleEase ease="0">

</SimpleEase></tweens></Keyframe>

<Keyframe index="59" tweenSnap="true" tweenSync="true" x="-200.00000000" y="0.00000000">

<tweens><SimpleEase ease="0"></SimpleEase></tweens></Keyframe>

</Motion>

</effect>

</effect_sequence>

Thanks

JackL