Not an area I specialize in, but quick research looks promising:
See Subtraction "H":
H. Foreign source income. If federal taxable income includes any amount that is "foreign source income," as that term is defined in § 58.1-302 of the Code of Virginia, and the provisions thereunder, such amount may be subtracted.
Which reference 58.1-302:
"Foreign source income" means:
4. Gains, profits, or other income from the sale of intangible or real property located without the United States;