r dygraphs shaded region by time of day across multiple days

In R dygraphs, how do I shade regions by time of day, across multiple days, without listing them each out? For example, I'd like to shade 07:00 - 08:15 each day in the following example (my full example has many more days).

#generate data
library(xts)
library(dygraphs)

#generate sample data
#http://stackoverflow.com/questions/9778632/r-xts-generating-1-minute-time-series-from-second-events
x <- xts(cumsum(rnorm(400000, 0, 0.2)), Sys.time() - 400000:1)
x <- to.minutes(x)

#display dygraph
dygraph(x) %>%
  dyCandlestick() %>%
  dyRangeSelector(height=20)

Thanks!

I was able to solve my problem. Code is below for reference:

Also, thanks to the following for ideas:

R xts: generating 1 minute time series from second events

R How to shade week-end period with dygraphs?

http://databasefaq.com/index.php/answer/20331/r-dygraphs-dyshading-r-dygraph

#load libraries
library(xts)
library(dygraphs)

#generate sample data
x <- xts(cumsum(rnorm(400000, 0, 0.2)), Sys.time() - 400000:1)
x <- to.minutes(x)

#display dygraph without shading
dygraph(x) %>%
  dyCandlestick() %>%
  dyRangeSelector(height=20)


#####################
#function to creating shading in a list
add_shades <- function(x, periods, ...) {
  for( period in periods ) {
    x <- dyShading(x, from = period$from , to = period$to, ... )
  }
  x
}

#####################
#creates the list that feeds into the "add_shades" function
ok_periods<-0
i=1
j=1
while (i<(length(index(x[(.indexhour(x)==9 & .indexmin(x)==30)])))){
  ok_periods[j] <- list(list(from = index(x[(.indexhour(x)==16 & .indexmin(x)==15)][i]), to = index(x[(.indexhour(x)==9 & .indexmin(x)==30)][i+1])))
  i=i+1
  j=j+1
}

#####################
#graph with shading
dygraph(x) %>%
  dyCandlestick() %>%
  add_shades(ok_periods, color = "#FFFFCC" ) %>%
  dyRangeSelector(height=20)