Question: Jet bundle with anticommuting variables (kind of...)

My question is this: 

In with(DifferentialGeometry): with(JetCalculus) with(Physics):

I work with the following Jet Bundle:

DGsetup([x], [u, psi], E, 40), 

where psi is declared anticommuting with Setup(anticommutativeprefix={psi}). 

When I work with expressions that are differential polynomials in u with coefficients arbitrary functions of u, the EulerLagrange operator behaves correctly. The same is true if I multiply these expressions by psi or by psi_1 (first derivative of psi with respect to x), or psi_{1,1} (second derivative of psi with respect to x) and so on. 

Also the program seems to recognize that psi * psi_1 =-psi_1 *psi and psi_1 * psi_1 =0. However, when I have expressions that are multiplied by psi * psi_1  and then I take the EulerLagrange operator I get the wrong answer. In particular

TotalDiff(psi * psi_1, x) is given equal to (psi_1)^2-psi * psi_{1,1}, while the result I need is psi * psi_{1,1}. 

So if I denote with D_x total derivative with respect to x, D_x should behave like this with respect to products of psi's:

D_x (psi * psi_{1} *psi_{1,1})=D_x (psi) * psi_{1} * psi_{1,1} + psi * D_x (psi_{1}) *psi_{1,1} + psi * psi_{1} *D_x (psi_{1,1}), but since D_x (psi)=psi_{1} and D_x(psi_{1})=psi_{1,1} we get psi * psi_{1} * psi_{1,1,1}. 

I also tried to introduce another anticommutative variable theta together with the x, but this does not work either. 

I am a complete newbie in using Maple, so any help will be greatly appreciated! (maybe there is a way to define rules for the action of the various operators on the psi variables... ?). 

Thank you very much!