Here is the operators manual it has info on the door removal and install.
http://www.whirlpool.com/digita...0Guide%20-%203196286.pdf

[COLOR="Blue"]When putting the door up to the oven at a 45 degree angle, something catches and as you pull the door downwards, the hinge does not move but all of a sudden it retracts back into the door.[/COLOR]
Sorry but I do not understand the above. Without being there I cannot be of much help.

[COLOR="Blue"]Is there some way to put something under the higes to keep them out?[/COLOR]
That is what the pins or bolts or whatever you sue is supposed to do.

Here are the parts for this unit
Parts for Whirlpool SF305PEEN0 Range - AppliancePartsPros.com
If you click on the description or picture of the hinges item 8 in the Door Parts section you will get a better view . They do seem to match the ones in the manual I sent.

The hinge plate has to be pulled down and then the pins put in place to hold it out away from the door.
Then push the door into the receivers in the unit. The door may have to be held at a bit of an angle to do this.
Then wiggle it so it drops some. This is to get the slots in the hinge to fit onto the pins in the receiver. You could have another person do this (wiggle and pulling downward while you hold the door.
This is to get the two pins in the receiver into the slots in the hinge plate.
So the door/hinge has to go in and then down.
Once the hinge is connected to the receiver pins you can lower it slightly and remove the pins you used to lock the hinge plate.

FYI: I am calling the part of the hinge mechanism that is inside the oven wall the receiver.

If all else fails try getting someone else to do this. Some folks are just lucky at getting things like this together.