> tssem2.2 <- tssem2(tssem2.1, 
+                  Amatrix = A2,
+                  Smatrix = S2,
+                  intervals.type = "LB",
+                  diag.constraints = TRUE,
+                  mx.algebras = list(indirectEffect = mxAlgebra(a*b, name="indirectEffect")))
> tssem2.2

Call:
wls(Cov = pooledS, aCov = aCov, n = tssem1.obj$total.n, RAM = RAM, 
    Amatrix = Amatrix, Smatrix = Smatrix, Fmatrix = Fmatrix, 
    diag.constraints = diag.constraints, cor.analysis = cor.analysis, 
    intervals.type = intervals.type, mx.algebras = mx.algebras, 
    model.name = model.name, suppressWarnings = suppressWarnings, 
    silent = silent, run = run)

Structure:
                 Length Class   Mode     
call             16     -none-  call     
Cov               9     -none-  numeric  
aCov              9     -none-  numeric  
noObservedStat    1     -none-  numeric  
n                 1     -none-  numeric  
cor.analysis      1     -none-  logical  
diag.constraints  1     -none-  logical  
Constraints       3     -none-  logical  
indepModelChisq   1     -none-  numeric  
indepModelDf      1     -none-  numeric  
mx.model          1     MxModel S4       
mx.fit            1     MxModel S4       
mx.algebras       1     -none-  character
intervals.type    1     -none-  character> summary(tssem2.2)

Call:
wls(Cov = pooledS, aCov = aCov, n = tssem1.obj$total.n, RAM = RAM, 
    Amatrix = Amatrix, Smatrix = Smatrix, Fmatrix = Fmatrix, 
    diag.constraints = diag.constraints, cor.analysis = cor.analysis, 
    intervals.type = intervals.type, mx.algebras = mx.algebras, 
    model.name = model.name, suppressWarnings = suppressWarnings, 
    silent = silent, run = run)

95% confidence intervals: Likelihood-based statistic
Coefficients:
            Estimate Std.Error       lbound       ubound z value Pr(>|z|)
b       -0.023514031        NA -0.218473352  0.176795884      NA       NA
c       -0.239276449        NA -0.376071546 -0.108083390      NA       NA
a        0.348132852        NA  0.248035022  0.448230294      NA       NA
Var_AV   0.938276434        NA  0.877105284  0.977357109      NA       NA
Var_Med  0.878803517        NA  0.799089561  0.938478285      NA       NA

mxAlgebras objects (and their 95% likelihood-based CIs):
                            lbound        Estimate        ubound
indirectEffect[1,1] -0.07808770636 -0.008186006614 0.06752595153

Goodness-of-fit indices:
                                                Value
Sample size                                1326.00000
Chi-square of target model                    0.00000
DF of target model                            0.00000
p value of target model                       0.00000
Number of constraints imposed on "Smatrix"    2.00000
DF manually adjusted                          0.00000
Chi-square of independence model             65.19075
DF of independence model                      3.00000
RMSEA                                         0.00000
RMSEA lower 95% CI                            0.00000
RMSEA upper 95% CI                            0.00000
SRMR                                          0.00000
TLI                                              -Inf
CFI                                           1.00000
AIC                                           0.00000
BIC                                           0.00000
OpenMx status1: 0 ("0" or "1": The optimization is considered fine.
Other values indicate problems.)