unfoldRepeats and : shortcut

[james]

Hello, I've discovered something that looks to be intentional behavior, just 
not expected. The : shortcut for tremolos doesn't expand in unfoldRepeats. Is 
the only way to get tremolos to expand to use the full notation?

\version "2.18.2"
test = \relative c' { \repeat tremolo 4 { <f a>16 e } \repeat tremolo 4 { <f g> 
d } a'2:8 g: }
\score { \new Staff \test }
\score { \new Staff \unfoldRepeats { \test } }

Thanks, James