Writter 4.5.1.3 how to validate digitaly signed document

[DrBuho]

I am having trouble to validate a digitaly signed document when using wrtter 4.5.1.3. The document appears signed, but writter does no validate it.
I work using OpenSUSE 13.1 32 bits and LibreOffice 4.5.1.3 and I am behind proxy.
What do you Suggest for validating these documents? Can it be acomplished by this version of LibreOffice or should i update it?
Thanks.-

[mikekaganski]

There was never version 4.5.1.3. The 4.x ended with 4.4; 5.0 was after that.