In an attempt to standardize my handling of formatting timestamps as text, I have added functions to "JDP Science Common Utilities" (a VI support package, on the Tools Network). This is used by SQLite Library (version just released) and JSONtext (next release), but they can also be used by themselves (LabVIEW 2013+). Follows RFC3339, and supports local-time offsets.
Is the 7-day trial for community edition or Base/Full/Pro? If it's for the later you can try just removing the license file from the usual license folder to see if it lapses into using the community edition license just fine.
I don't know how exactly how the community edition is licensed but that type of thing happens a decent amount with volume license servers (LV complains about software that's about to expire but once it expires it just finds another license and is perfectly happy).