You will need to program rs.Command() with _TextObject in this case. Following is a quickie example…
import rhinoscriptsyntax as rs
def AddTextObjectAsCurves():
tol=rs.UnitAbsoluteTolerance()
text=rs.GetString("Enter your text")
if text==None: return
ht=rs.GetReal("Text height?",minimum=tol)
if ht==None: return
commStr="-_TextObject _GroupOutput=_Yes _FontName=Arial "
commStr+="_Italic=_No _Bold=_No "+str(ht)+" _Output=_Curves "
commStr+="_AllowOpenCurves=_No _LowerCaseAsSmallCaps=_No "
commStr+="_AddSpacing=_No "+text
rs.Command(commStr,True)
AddTextObjectAsCurves()
--Mitch