Semi-Regular Time Series with Missing Values

Hi,

I'm trying to make a ts object that has both NA values and a frequency other
than 1 (so I can use stl). I've tried all permutations I can think of, but
cannot get the desired (expected?) results.

The values live in x and the corresponding semi-regular time stamps are in
t:

library('zoo')
z = zoo(x, order.by=t, frequency=24)
zzr = as.zooreg(z, start=0)
zr = zooreg(x, order.by=t, start=0, frequency=24)
zrz = as.zoo(zr)

The objects z, zr, and zzr all have frequency 24, as desired, and plot
correctly. Object zrz plots correctly but has frequency 1. Now I try to make
it a ts object:

zrt = ts(zzr)

... omits the missing values.

zrt = ts(zzr, frequency=24)

... omits the missing values and changes the timestamps.

plot(ts(zr))

... omits the missing values.

zrt = ts(zr, frequency=24)

... omits the missing values and changes the timestamps.

zrt = as.ts(zr)

... inserts 23 NA values between each legitimate value.

zrt = as.ts(zr, frequency=24)

... inserts 23 NA values between each legitimate value.

zrzt = ts(zrz)

... omits the missing values.

zrzt = ts(zrz, frequency=24)

... omits the missing values and changes the timestamps.