As noted by makin' miles, alaska changed their award structure awhile back and the lowest AS award to Hawaii is 20,000 miles. If you want to use avios for AS flights you can only use them for this lowest level award.

If you search alaskaair.com and tick the box to use miles and tick the box for award calendar you can see the days when 20,000 mile awards are avialable. For example, searching for 4 adults SAN-OGG you can see on the calendar that 20,000 mile awards are available on 25MAR14. If you look further you will find that this 20,000 mile award is actually SAN-PDX, PDX-OGG (with a long layover in PDX). Using avios this award should be available by calling BAEC and will cost you in avios:
SAN-PDX - 933 miles - 7500 avios
PDX-OGG - 2562 miles - 12500 avios
or a total of 20000 avios per person one way.

Looking at the alaskaair.com award calendar you can see that there are no lowest level awards (20,000) available on the dates you want to return and so you could purchase one-way tickets on AS for your return.