The .tr0, .ac0 files are Synopsys proprietary formats for HSPICE, and as such, ViVA does not read them. However, HSPICE can output PSF directly, and that would normally be done by setting:
.OPTION ARTIST=2 PSF=2
If it is not writing PSF, then you should contact Synopsys. As you say, the alternative is to use Synopsys' translator - Cadence do not provide a translator for the same reason; we provide libraries to allow third-party simulators to write a format that ADE/ViVA can read.