I really appreciate if someboy can help me with this, I have a Draw with AEC objects and I need to insert this in another draw like a block but I can't do it because all the AEC objects disappear, Only can I insert the draw like using XREF but I need insert also other draws with AEC objects the draw it grows so much.  I hope somebody will have a solution to this.   

solve my problem in the following way:

a.- use the xref command
b.- load the file where the AEC objects are
c).- Once there, before closing the reference files window, right click with the mouse on the file that has just been entered, there the Bind option is selected and in this one select insert and ok.
d).- In this way the AEC objects are introduced as a block.