Items

When trying to link different costs to differest assets I am using 'items' for the assets. I then have transactions with different expense accounts such as one transaction is for repairs and maintenance and the next transaction is for the vehicle license. When I slect the asset item ID it only allows me to use the expense account that is set up for that item. If this is how MYOB works, can anyone offer another suggestion on how to do it a different way that suits MYOB? The MYOB help said I can change the item ID linked code each time before I allocate a transaction but that seems owneress and if a transaction needs to be split to say fuel and repairs and maintenance, I can't link both the fuel and repairs and maintenance to the the item.