IRF for Model

[malibu_ce2]

Using Eviews9 How can I calculate by hand or with eviews an IRF if I have this spezific model : and how to transform it in a singel VAR equation if necessary (to finde IRF)? and why is the resulta different if I do this estimation (LS XGMT C AR(1) RWI(0) BIPD(0))?

Estimation Command:
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LS XGMT C XGMT(-1) RWI(0) BIPD(0)

Estimation Equation:
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XGMT = C(1) + C(2)*XGMT(-1) + C(3)*RWI + C(4)*BIPD

Substituted Coefficients:
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XGMT = 0.00842907135776 + 0.179982856041*XGMT(-1) - 0.198731150282*RWI - 0.000231563438015*BIPD

Xgmt, rwi, Bipd are diffloged variables ... I want to finde out how xgmt reacts when rwi is changing. (elastizity)