In order for an asset to be recognized in the financial statements, it must the following definition laid down in the IASB Framework:
Asset is a resource controlled by the entity as a result of past events and from which future economic benefits are expected to flow to the entity (IASB Framework).
In your case, the asset does not meet the recognition criteria under IASB Framework. Only once you get the control of the asset, you can recognize it in your books.
Entries for the transactions mentioned above should be:
Downpayment ($ 30,000)
Dr. Advances to suppliers
Progress Payment ($ 60,000)
Dr. Advance to Suppliers
Final Payment on delivery ($ 10,000) - Time to recognize asset:
Dr. Asset 100,000
Cr. Advances to suppliers 90,000
Cr. Bank 10,000