How to Get License UDI for installing Firepower Services on 5500X running with ASDM ?

[Hassan Hameed]

Hello!
I have 5500x series firewall in production running on ASDM now i want to buy a Firepower Services license so for that i need to know the UDI of firewall how can i get license UDI?
Note: Right now i have no ASA Firepower configuration tab in ASDM and i also cant get down time.

[balaji.bandi]

from command level  you can try ( is that what you looking ?)

show license udi 

[Hassan Hameed]

No, Actually there is firepower tab missing from ASDM so i want to know how to install Firepower services (to find firepower udi to buy license) with zero firewall downtime?