howling in crate

Question
Two months ago I rescued a Basenji mix.  She is now about seven months old and has been a champ with housetraining.  I crate trained her and it worked really well.  I walk her twice a day (20-40 min each walk).  I crate her when I leave the house and have recently discovered that she howls in her crate when she has to go to the bathroom.  My neighbors mentioned they heard her howl (being her main breed is basenji, she doesn't really bark but makes a howl-yodel noise), and the other night I came home and heard her from the alley behind my apartment building.  It was loud!  How can I get her to stop?  She's doing it because she needs something--to go to the bathroom.  She is trying to tell me something, but I am not home to hear it.  I don't leave her for more than 5 hours and I know she can hold out that long, because she does when I'm home and she is holding it while she is in the crate.  She is just trying to alert me.  She runs straight for the front door when I let her out of the crate on these occasions.

Answer
I have never had a puppy that couldn't go 5 hours well before 7 months.  Yours could be different.  It could also have a UTI.  Talk to the vet about the problem.  She may need more breaks.  Could a neighbor or a professional dog walker give her one?  The ultimate is doggie daycare.  

If any of my puppies made enough noise for the neighbors to hear, they never said anything.  Nobody ever has said anything about my puppies setting the neighbors' dogs to barking either.