To add new reimbursables, I'd display the area in the project manager. This way it's easier to view all entries. Show the Reimbursables by hitting the "Display areas" button.
Mark the project you want to create a reimbursable for and hit either the "Add reimbursable" button above your project list or the green plus button in your Reimbursables/Costs area.
A dialog will open, where you can add the reimbursable expense. You can add as many details as you like.
Under the "General" tab, you can also enter an individual name for the service to be entered, which you can add to the service catalog if you wish. The name can then be displayed on the invoice.
Also assign new custom fields by right-clicking. Select "Rename" to label the fields as you wish.
After you've entered all necessary details, click on save and you new reimbursable expense will show up in your reimbursables:
Xpert-Timer supports different currencies. So if you have reimbursables, that need to be saved in another currency than your standard currency you can do so. But please keep in mind, that if you use different currencies, you cannot calculate a total sum, as it wouldn't make sense.