Question: Warning, may some solutions left / intersection point

Hello everybody,

I try to find the intersection point for the following equation, but I didn't get any or just "warning, ..." where is the problem? and how can I solve this!?

> S1 := proc (t) options operator, arrow; F[1](t)*m[1]*(1-F[2](t)) end proc;
> S2 := proc (t) options operator, arrow; F[2](t)*(m[2]+F[1](t)*m[1]) end proc;
> F[1] := proc (t) options operator, arrow; (1-exp(-(p[1]+q[1])*t))/(1+q[1]*exp(-(p[1]+q[1])*t)/p[1]) end proc;
> F[2] := proc (t) options operator, arrow; piecewise(tau < t, (1-exp(-(p[2]+q[2])*(t-tau)))/(1+q[2]*exp(-(p[2]+q[2])*(t-tau))/p[2]), t <= tau, 0) end proc;

> s1 := proc (t) options operator, arrow; eval(S1(t), [p[1] = 0.4e-1, q[1] = .29, m[1] = 730.60, tau = 7, p[2] = 0.2e-1, q[2] = .42]) end proc; s2 := proc (t) options operator, arrow; eval(S2(t), [p[1] = 0.4e-1, q[1] = .29, m[1] = 730.60, tau = 7, p[2] = 0.2e-1, q[2] = .42, m[2] = 1104.64]) end proc; s1(t); s2(t); solve(s1(t) = s2(t));