Advance payments-Disbursement and Billable expenses

I love the interface of the Manager and I would love to use it for my business. I read lots of postings and I must admit that the forum makes good bedtime reading material. I would love to benefit from all features this program has to offer. I kindly request your assistance in the following case scenario.
Small Immigration Consultancy Firm (migration agent/lawyer).

Here are my journal entries:

	                              DR	CR
Trust Bank	            5000	
Advance payment		      5000

	                                                                                                    DR	CR
Billable Expenses 
(visa applic charge to the IMMI Dep payable on behalf of client)               3000	
Trust Bank	                                                                           	               3000

	                                                                   DR       CR
Advance payment	                                         5000	
Billable expenses		                                              3000
Service Fee
(when invoice is raised to the customer)		              2000

	                                                                    DR	CR
Operation Account
(when job completed and invoice issued)	        2000	
Trust Bank		                                                       2000

I must add that the advance payment a/c balance does not always clear at the time when invoice is raised. It may include for services which will be performed in the next 6 months where the final invoice will be raised when that particular block of service will be finalised.
How would you run these transactions using the Manager? What’s the “textbook” way of running these transactions through the existing modules (Bank, Sales, Purchases etc) . If I don’t ask for toooo much, could any of the experts run a step by step procedure?
Thank you for your time and consideration!

The only way to clear billable expense is through issuing them a sales invoice.

Also, when you issue them sales invoice, advance payment will be automatically applied to that invoice - no need for journal entry (assuming you are taking advantage of control account called Customer credits)

Thank you Lubos.