If you want that the door opens immediately if you pick up the item use a normal Remote Door and give it a new name like "mydoor".
Then you have to make a little change in the "pickup" script.
Add the fat text to the code:
:state=0:hudreset,hudx=50,hudy=90,hudimagefine=gamecore\text\pickedupanitem.tga,hudname=itemprompt,hudhide=1,hudmake=display,state=10
:state=10,plrdistwithin=40:state=1,
activateifused=1,playertake,coloff,plrsound=audiobank\misc\ping.wav,hudshow=itemprompt,hudfadeout=itemprompt
:state=1:rundecal=5
Save this script with a new name, attach it to your entity and tipe the name of the Remote Door (mydoor) in the "If Used" Field of the Entity.
Then the door should open immediately if you pick up the entity.
A other way would be to use the entity like a Key for a Switch that opens a Remote Door if you have the Entity.
For that you have to make a Remote Door again and give it a new name (mydoor02).
Add your entity to the level and make sure that the default "pickup1.fpi" is attached to the entity.
Important: Give the entity a new name (myitem).
Add your switch to the level and attach this changed "switch" script to it:
;Artificial Intelligence Script
;Header
desc = Switch Activate (toggle on and off) ---------->PLR needs a Key (Item)<---------
;Triggers
:state=0:hudreset,hudx=50,hudy=90,hudimagefine=gamecore\text\pressentertouse.tga,hudname=useswitchprompt,hudhide=1,hudmake=display,state=20
:state=20:hudreset,hudx=50,hudy=90,hudimagefine=gamecore\text\lockeddoor.tga,hudname=keydoorprompt,hudhide=1,hudmake=display,state=10
:plrdistwithin=50,plrhaskey=0:hudshow=keydoorprompt,hudfadeout=keydoorprompt
:plrdistwithin=50,plrhaskey=1:hudshow=useswitchprompt,hudfadeout=useswitchprompt
:state=10,plrdistwithin=50,plrusingaction=1,plrhaskey=1:state=1,plrsound=audiobank\scifi\scenery\switchesactivate.wav,activateifused=1,alttexture=1
:state=1,plrusingaction=0:state=2
:state=2,plrdistwithin=50,plrusingaction=1:state=3,plrsound=audiobank\scifi\scenery\switchesactivate.wav,activateifused=0,alttexture=0
:state=3,plrusingaction=0:state=10
;End of Script
Finally you have to tipe the name of the door (mydoor02) in the "IF Used" field of the switch and the name of the entity (myitem) in the "Use Key" field of the switch.
I have tried both versions and it worked for me.