Newbie How-To Questions on Credit Cards & Vendors and Cost-Centres

[Peter C. Pugh]

Hello,

I have searched Google a number of times to try and find an answer to  
this question.  Sorry if I have overlooked any previous postings.

I am trying to establish how to use Vendors in conjunction with  
Credit Cards.  I.e. ...

1.	You go to a supplier and purchase an item.  The Supplier is  
defined as a Vendor in GNUCash.
2.	You enter the purchase against the appropriate Vendor and record a  
payment which is settled through a Credit Card.
3.	The Vendors transaction goes to the associated Expense account and  
as a Credit Card Liability.
4.	You then get the Credit Card statement with the charge showing for  
the purchase.
5.	A payment is made to the Credit Card company, although it is late.
6.	This ISN'T paid in full in that period -- hence it attracts an  
interest charge in the following period.
7.	Subsequently, due to the late payment, there is also an additional  
charge applied by the Credit Card company.

Essentially, what I am trying to understand is the appropriate  
structure that should be in-place to support such a transaction  
scenario.  Should the Credit Card company also be registered as a  
Vendor to reflect the associated Interest and Late Payment charges?   
With Vendors in place, should the Credit Card company's statement be  
settled as a Vendor account, or just as a Credit Card Liability  
account?  Should the original transaction even be processed as a  
Vendor transaction, or straight to the Credit Card account, bypassing  
the Vendor phase entirely?

An additional question as well please ...

How do you track expenses back to the individual that made the  
purchase?  I.e.  Define a Cost/Profit Centre for each member of the  
organisation who may be making purchases or settling accounts?   
Currently I use a structure like ..

Expense
     |
     |---Miscellaneous
               |
               |---CC-1
               |---CC-2
               |---etc.
     |
     |---etc.

Is there any other way to record a Cost-Centre type structure or Cost- 
Centre type information?

For your information, I am using GNUCash 2.0.1 on a MacBook Pro.  I  
am using it for personal and small business (sole trader) accounts.   
The reason I am wanting to use Vendors is so that I can track not  
just the nature of each transaction -- the expense type -- but also  
the places that the expenses are incurred.  As well as that, I often  
work on a project basis, and need to be able to relate some expenses  
back to a client  for billing purposes.

Thank you.