Since you can now remove objects here's how you get the IDs.

First off, download JerenjL's map editor, it will make this way easier.
    [url]http://forum.sa-mp.com/showthread.php?t=282801[/url]
Next: install the map editor by extracting the files to your GTA installation folder. 
//no picture needed
Then: go into the map editor, and select the object you want. It should turn red.
//See picture one
Now: press delete and it will delete the object
Lastly: Click the "Show Code" button and paste that code into your GM.
//See attached .bmp