Question: Parentheses and units in odeplot legend

Hi there,
I am wondering how to print parentheses in the legend of an odeplot.

The following command

odeplot(numsolnf, [[t, CECnf(t)], [t, VECnf(t)], [t, CICnf(t)], [t, VICnf(t)]], 0..50, opts, legend = ['Extracelular urea concentration (mg/dL)', 'Extracelular urea volume (L)', 'Intracelular urea concentration (mg/dL)', 'Intracelular urea volume (L)'])

where numsolnf is the numerical solution of the equation system composed by CECnf(t), VECnf(t), CICnf(t), and
VICnf(t) produces no parentheses.

And the "Extracelular urea concentration (mg/dL)" and "Intracelular urea concentration (mg/dL)" are displayed as if the whole text was a quotient:

Extracelular urea concentration mg
dL

Any ideas about how to solve these issues?

Thanks,
jon