scripting omnigraffle

Dear scripters ,

I am scripting an omnigraffle application . Is there any way from which i can group the graphics of the front document or canvas and align them in the center of canvas ( vertically and horizontally).Any help in this case will be of great help , specially if any component of this problem get solved .

The components are :
1.how to put the single graphics in the center of the canvas ?
2.how to group the different graphics ?
3.how to put the grouped graphics in the center of the canvas ?

Thanks in advance .

regards

Krishna

I reach upto the certain extent of the problem , how to group the graphics , for this syntax is :

tell front document of application “Omnigraffle Professional”
tell front canvas
–this part assembles the mentioned graphics
assemble {graphic 1 , graphic 2 }
end tell
end tell

This groups the mentioned graphics and treat them as one . Now the question is how to align grouped graphic with the canvas either vertically or horizontally ? Any help or suggestions highly appreciable .

Kind regards

Krishna