I have four regressions and I am trying to plot only the coefficients of the interaction terms, using coefplot.

Code:
sysuse auto, clear

reg price c.turn##i.foreign, r
eststo m4
reg price c.weight##i.foreign, r
eststo m3
reg price c.headroom##i.foreign, r
eststo m2
reg price c.mpg##i.foreign, r
eststo m1

coefplot (m1,label("Mileage")) (m2,label("Headroom")) (m3,label("Weight")) (m4,label("Turn")), keep(c.turn##i.foreign c.weight##i.foreign c.headroom##i.foreign c.mpg##i.foreign) vertical
When I run the do-file Stata stops before plotting the coefplot and types:

coefplot (m1,label("Mileage")) (m2,label("Headroom")) (m3,label("Weight")) (m4,label("Turn")), keep(c.turn##i.foreign c.weight##i.foreign c.headroom##i.fo
> reign c.mpg##i.foreign) vertical
(m1: no coefficients found, all dropped, or none kept)
(m2: no coefficients found, all dropped, or none kept)
(m3: no coefficients found, all dropped, or none kept)
(m4: no coefficients found, all dropped, or none kept)
(nothing to plot)
Is there a solution or any other way to this? It works when I want to plot the independent variables (i.e. turn weight headroom mpg).