Distinction of different types of missing values is lost after importing data from SPSS into R

I've got a file containing survey data in SPSS. There are 3 types of missing values defined: invalid (coded as 900), not applicable (990), not filled in (999). After importing the SPSS file into R using haven library, all types are coded as "NA", the distinction is lost. How do you deal with this if distinction is important?