Forest Trust - Trusting domain cannot see child domain of trusted domain

Environment:

Forest A has a parent and child domain
 -DomainA.Local
 -Child.DomainA.Local

Forest B has a single domain
-DomainB.Local

I setup a 1-way Forest trust (transative) between DomainA.Local and DomainB.Local where DomainB trusts DomainA.  This is working well and DomainB can "see" DomainA, I.E., the domain is listed in the drop down for logon to, it is a location I can use when adding members to domain local groups, etc. 

I cannot, however, "see" the child domain of DomainA (Child.DomainA.Local) from DomainB.  My understanding was that the Forest trust was supposed to be completely transative, therefore, DomainB should trust any domain that DomainA trusts.

I did some further testing and added another trust, this time an External form DomainB.Local to Child.DomainA.Local.  I did not remove the orignal Forest Trust.  With this in place I am able to "see" Child.DomainA.Local form DomainB.Local

Is this how I will have to leave it or am I missing somethign with my original Forest Trust?  Thanks!

--Kevin