What i have to pass in old image if its a Insert case for a change doc. obj.?

Hello

I have created a custom change document object thru SCDO tx for a my_table, well.

Now, i have to use the generated FM of *WRITE_DOCUMENT in my custom prog,. wherein my_table is updating, I am aware of that if its a Update / U case, then, i have to pass U indicator together with the OLD image in Y str. and NEW image in X str., well, but, pls. let me know ,

1) Insert case / I: What i have to pass for OLD / Y image?

2) Delete case / D: What i have to pass for NEW / X image?

3) And users are doing from WebDyn Pro / Portla screens, in this case, what Transaction code i have to pass to importing param of WRITE FM?

Thank you