Rotating time axis labels

[<Russell.Fiedler@xxxxxxxxxxxxxxx>]

Greetings Ferreteers,

The plot so far...
I've created a a shade plot of SST along the equator in the Pacific over a
period of 10 years. Unfortunately the labelling of the (vertical) time axis
leaves a lot to be desired. All the years are labelled such that they are 
rotated 90 degrees to the plot. Forcing too many labels via PPL TXLINT causes
them to overlap. Reducing the size of the labels is a poor option too.
A complicating factor is that this plot is to be in the upper panel with another
below it. 

e.g.

! sst has monthly values
! typical "upper" view port, actually there are few game played with the margins
! but that's not important here.

def view/x=0,1/y=0.4,1 u
set view u
! shade
shade/x=140:290/l=1:120/set sst
!set axis labels size to about minimum readable
ppl txlsze 0.06
! suppress monthly label and label every second year (ideally every year)
ppl txlint ,2
ppl shade

Is there an elegant way of rotating the T axis labels? I know that I can put
them on manually or play some tricks by regridding to a non calendar grid but
that's not really satisfactory in the long term.

Cheers,

Russ Fiedler