5304 Autodial Key COS/COR Independent Account Code

[HBIT]

Hi everyone,
I'm trying to configure a phone Mitel 5304 to dial a number when a button is pressed. Telephone currently has COS/COR lined pemanently blocked until the Independent Account Code (IAC) is dialed.

Is there a way to configure the button in order to dial IAC + number in one single press?

I'm trying to enble User-Speed Call and Private User Speed call features with no success.
When the button is pressed it shows the message dial number, after it's pressed a second time it shows the number to dial and that's it no call i performed.

Any help will be appreciated.

Thank you
HBIT