Define leased assets with 999 years of life

We have a requirement where in using 999 years of life for assets (commonly leased assets) is a common practice in United Kingdom. But if we try to create a STL method with 999 years of life (i.e. 11998 months) it is not being allowed by the Oracle system. The maximum it can support is 10000 months, which means 833 years and 3 months.

Is there a way we can by-pass this limitation and setup assets with 999 years of life (11998 months)?

Thanks