Timeserie backend based on the R-metrics package timeSeries. The timeSeries package provides a S4 class definition for univariate and multivarate analysis.
To install timeSeries, launch R (R http_proxy=http://your.proxy.com if behind a proxy server) and type:
install.packages("timeSeries")
From an implementation perspective, the rmetrics timeserie backend is different from the zoo implementation because of RS4 objects are a little more formal regarding their class definition, and all instances belong to the low-level R type SEXPS4.