Custom Format Numbers for account codes

I need to format a cell so that it will always display the account code directly when managers are entering information into their requisition form. Our account format needs to be:

4444.4444.22.22

I guess dots or dashes wouldn't necessarily matter. I have tried some formats, but I don't get the results I am hoping for.

It just needs to be 4 digits, dot, 4 digits, dot, 2 digits, 2 digits.

Any suggestions? Thank you!