Thermal resistance in K*m^2/W or material/thickness definition.. ?

I am trying to model a TO-247 transistor on a heat sink.

The data sheet gives :

Thermal Resistance from Junction to Case 0.27 °C/W

Thermal Resistance from Junction to Ambient 40 °C/W... and no other information about materials (case, chip, bonding material, thermal pad, connection pads).

After searching a little bit on the internet I can make the following hypothesis :

1. case - epoxy resin

2. chip - SIC (4H-SiC, or 6H-Si-C)

3. Thermal pad - cooper

4. Connection pads -cooper

For the bonding material I have no idea...so the only way to define it should be through a contact resistance between the case and the junction....

If I choose to use material/thickness definition I have to approximate chip material&thickness.. so I do not know if it will be accurate.

The problem is that I do not know how to convert the RTH junction to case given by the manufacturer data sheet (°C/W) and the Contact resistance required in SW Flow simulation which is in K*m^2/W ...

Can anyone help me ?

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